GMAT Club Forum - Forums > Data Sufficiency (DS) https://gmatclub.com:443/forum/index.php MBA Forum, Business School Application, GMAT Tests, Business School Essays, Interviews, GMAT Forum and Tests en-gb Copyright (c) 2002 GMAT Club Forum mail@gmatclub.com (GMAT Club Forum) mail@gmatclub.com (GMAT Club Forum) Mon, 25 Sep 2017 00:00:00 -0800 Mon, 25 Sep 2017 12:10:15 -0800 MSSTI RSS Feed 2.0 Version 1.0.9 - (C) 2008-2009 leviatan21 - http://www.mssti.com/ GMAT Club Forum - Forums > Data Sufficiency (DS) https://gmatclub.com:443/forum/styles/gmatclub_light/imageset/site_logo.gif https://gmatclub.com:443/forum/index.php 60 Problem Solving (PS) | Re: Brian plays a game in which two fair, six-sided dice are rol https://gmatclub.com:443/forum/viewtopic.php?p=1932150#p1932150
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Data Sufficiency (DS) | How many 4 member committee can be formed from a group https://gmatclub.com:443/forum/viewtopic.php?p=1932148#p1932148 thanhtam269 wrote:

(1) definitely not sufficient alone, cause we need to know how many men and women (not how many total of men and women).
(2) is also not sufficient. Let's assume that x and y both larger than or equal to 3, so the number of committees that can be formed is (3Cx * 1Cy) + (1Cx * 3Cy)
Clearly if we swap x and y this sum is not changed, so (2) is always right for x, y >= 3
Combine (1) and (2) we see that (x, y) can be (3, 9), (4, 8), (5, 7) or (6, 6), hence we still can't calculate the result.

=>

...
]]>
thanhtam269 wrote:

(1) definitely not sufficient alone, cause we need to know how many men and women (not how many total of men and women).
(2) is also not sufficient. Let's assume that x and y both larger than or equal to 3, so the number of committees that can be formed is (3Cx * 1Cy) + (1Cx * 3Cy)
Clearly if we swap x and y this sum is not changed, so (2) is always right for x, y >= 3
Combine (1) and (2) we see that (x, y) can be (3, 9), (4, 8), (5, 7) or (6, 6), hence we still can't calculate the result.

=>

...]]>
(victor123897)https://gmatclub.com:443/forum/viewtopic.php?p=1932148#p1932148
Data Sufficiency (DS) | Re: The number of touchscreen personal organizers currently in stock is p https://gmatclub.com:443/forum/viewtopic.php?p=1932140#p1932140
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Problem Solving (PS) | Re: From a jar containing 4 red and 2 white marbles, Lionel draws two marb https://gmatclub.com:443/forum/viewtopic.php?p=1932137#p1932137
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Data Sufficiency (DS) | Families in which some members argue with each other compete for a cha https://gmatclub.com:443/forum/viewtopic.php?p=1932135#p1932135 rahulkashyap wrote:

Still unclear how you got only 50 percent of the family arguing. Would be helpful if you took numbers to show that. For example, 6 men and 6 women. 6 men argue with each other and 6 women argue with each other.
That's 12 people (100%) arguing. 8 men and 4 women would not change the percentage.

Posted from my mobile device

Hi Rahulkashyap, Here is how I got 50 percent arguing with each other.

The question states :The greater the percentage of family members who argue with each other, the greater
...
]]>
rahulkashyap wrote:

Still unclear how you got only 50 percent of the family arguing. Would be helpful if you took numbers to show that. For example, 6 men and 6 women. 6 men argue with each other and 6 women argue with each other.
That's 12 people (100%) arguing. 8 men and 4 women would not change the percentage.

Posted from my mobile device

Hi Rahulkashyap, Here is how I got 50 percent arguing with each other.

The question states :The greater the percentage of family members who argue with each other, the greater
...]]>
(victor123897)https://gmatclub.com:443/forum/viewtopic.php?p=1932135#p1932135
Data Sufficiency (DS) | When a player in a certain game tossed a coin a number of https://gmatclub.com:443/forum/viewtopic.php?p=1932122#p1932122 1. Coin is tossed 24 times ----> H + T = 24 ----> H + (H -4) = 24. Sufficient
2. Head gets 3 points and tails 1 point
Hence, 3H + T = 52 -----> 3H + (H-4) = 52. Sufficient.

]]>
1. Coin is tossed 24 times ----> H + T = 24 ----> H + (H -4) = 24. Sufficient
2. Head gets 3 points and tails 1 point
Hence, 3H + T = 52 -----> 3H + (H-4) = 52. Sufficient.

(devanshu92)https://gmatclub.com:443/forum/viewtopic.php?p=1932122#p1932122
GMAT Club Tests | Re: M09-22 https://gmatclub.com:443/forum/viewtopic.php?p=1932120#p1932120 akitrav wrote:

I think this is a high-quality question and I don't agree with the explanation. x > -1 means x could be 1 and 1 is not less that 1. Can anyone elaborate?

This is a tough question. I suggest you re-read the WHOLE thread carefully.
]]>
akitrav wrote:

I think this is a high-quality question and I don't agree with the explanation. x > -1 means x could be 1 and 1 is not less that 1. Can anyone elaborate?

This is a tough question. I suggest you re-read the WHOLE thread carefully.]]>
(Bunuel)https://gmatclub.com:443/forum/viewtopic.php?p=1932120#p1932120
Problem Solving (PS) | Re: A bag contains 15 wool scarves, exactly one of which is red and exactl https://gmatclub.com:443/forum/viewtopic.php?p=1932116#p1932116
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Problem Solving (PS) | Re: At a blind taste competition a contestant is offered 3 cups https://gmatclub.com:443/forum/viewtopic.php?p=1932114#p1932114 DanceWithFire wrote:

cledgard wrote:
I solved it in a way that I think is more direct:
I get the probability that each cup is not a specific type of tea (type A):
1st cup, Probability it is not type A = 3/9
2nd cup, Probability it is not type A = 3/8, since we only have 8 cups left, and 3 of them are type A
3rd cup, Probability it is not type A = 3/7
4th cup, Probability it is not type A = 3/6
We do the same for types B and C (multiply by 3)
So : 3/9 * 3/8 * 3/7 * 3/6 * 3 = 5/14

1st cup : 3/9 is actually the probability
...
]]> DanceWithFire wrote:

cledgard wrote:
I solved it in a way that I think is more direct:
I get the probability that each cup is not a specific type of tea (type A):
1st cup, Probability it is not type A = 3/9
2nd cup, Probability it is not type A = 3/8, since we only have 8 cups left, and 3 of them are type A
3rd cup, Probability it is not type A = 3/7
4th cup, Probability it is not type A = 3/6
We do the same for types B and C (multiply by 3)
So : 3/9 * 3/8 * 3/7 * 3/6 * 3 = 5/14

1st cup : 3/9 is actually the probability
...]]> (cledgard)https://gmatclub.com:443/forum/viewtopic.php?p=1932114#p1932114 Problem Solving (PS) | Re: If (5/4)^(-n) < 16^(-1). What is the least integer value of n? https://gmatclub.com:443/forum/viewtopic.php?p=1932112#p1932112 )
(5/4)^(−n)<16^(−1)
(4/5)^n<1/2^4
so left side should be less than 1/2

we raise to cube
(4/5)^3=64/125 and multiply right side by 64 just to compare, makes 64/128, so the inequality is still not satisfied but just a bit, it's clear that if multiply the left side by 4/5 one more time the inequality will be respected
But as we have 4 power on the right 1/2^4
then
...
]]>
)
(5/4)^(−n)<16^(−1)
(4/5)^n<1/2^4
so left side should be less than 1/2

we raise to cube
(4/5)^3=64/125 and multiply right side by 64 just to compare, makes 64/128, so the inequality is still not satisfied but just a bit, it's clear that if multiply the left side by 4/5 one more time the inequality will be respected
But as we have 4 power on the right 1/2^4
then
...]]>
(cbh)https://gmatclub.com:443/forum/viewtopic.php?p=1932112#p1932112
Quant Question Archive [LOCKED] | Re: Problem#101: A student committee on academic integrity has https://gmatclub.com:443/forum/viewtopic.php?p=1932105#p1932105
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Data Sufficiency (DS) | Re: New Set: Number Properties!!! https://gmatclub.com:443/forum/viewtopic.php?p=1932104#p1932104 Bunuel wrote:

9. If [x] denotes the greatest integer less than or equal to x for any number x, is [a] + [b] = 1 ?

Given that some function[] rounds DOWN a number to the nearest integer. For example[1.5] =1,[2] =2,[-1.5] =-2, ...

(1) ab = 2. First of all this means that a and b are of the same sign.

If both are negative, then the maximum value of[a] +[b] is -2, for any negative a and b. So, this case is out.

If both are positive, then in order[a] +[b] = 1 to hold true, must be true that[a] =0 and[b] =1 (or vise-versa). Which means that

...
]]>
Bunuel wrote:

9. If [x] denotes the greatest integer less than or equal to x for any number x, is [a] + [b] = 1 ?

Given that some function[] rounds DOWN a number to the nearest integer. For example[1.5] =1,[2] =2,[-1.5] =-2, ...

(1) ab = 2. First of all this means that a and b are of the same sign.

If both are negative, then the maximum value of[a] +[b] is -2, for any negative a and b. So, this case is out.

If both are positive, then in order[a] +[b] = 1 to hold true, must be true that[a] =0 and[b] =1 (or vise-versa). Which means that

...]]>
(Ace800)https://gmatclub.com:443/forum/viewtopic.php?p=1932104#p1932104
Data Sufficiency (DS) | Re: A circle with center (1, 0) and radius 2 lies in the https://gmatclub.com:443/forum/viewtopic.php?p=1932102#p1932102
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Data Sufficiency (DS) | Re: Triangle RST lies in the xy-plane. Point R has coordinates (a,b), poin https://gmatclub.com:443/forum/viewtopic.php?p=1932098#p1932098
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Data Sufficiency (DS) | Re: If n is an integer and f(n) = f(n 1) n, what is the value of https://gmatclub.com:443/forum/viewtopic.php?p=1932097#p1932097
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GMAT Club Tests | Re: M20-08 https://gmatclub.com:443/forum/viewtopic.php?p=1932092#p1932092 oirfan wrote:

How is statement 1 sufficient?

If we pick numbers for statement 1 we can get two different answers.
if x=2 and y=3, then 100-3=97, Answer NO
if x=2 and y=9, then 100-9=81, Answer YES

Am I missing something?

Even I make such mistakes, be careful. How should one avoid such mistakes?
]]>
oirfan wrote:

How is statement 1 sufficient?

If we pick numbers for statement 1 we can get two different answers.
if x=2 and y=3, then 100-3=97, Answer NO
if x=2 and y=9, then 100-9=81, Answer YES

Am I missing something?

Even I make such mistakes, be careful. How should one avoid such mistakes?]]>
(aashishagarwal2)https://gmatclub.com:443/forum/viewtopic.php?p=1932092#p1932092
Problem Solving (PS) | Johan rides his bicycle to and from college everyday https://gmatclub.com:443/forum/viewtopic.php?p=1932083#p1932083 longhaul123 wrote:

I have a small doubt the circumference and the rotation around the circle gives the same meaning right? Because when we say revolving around the circle we mean it is 1 rotation= going around the circumference. Is this not right??

No, they are not the same in that circumference gives you the actual distance and rotations dictate the number of times the actual distance is multiplied. Circumference is constant, rotations change.

For e.g., if the wheel's circumference is 2 mts (just for the sake
...
]]>
longhaul123 wrote:

I have a small doubt the circumference and the rotation around the circle gives the same meaning right? Because when we say revolving around the circle we mean it is 1 rotation= going around the circumference. Is this not right??

No, they are not the same in that circumference gives you the actual distance and rotations dictate the number of times the actual distance is multiplied. Circumference is constant, rotations change.

For e.g., if the wheel's circumference is 2 mts (just for the sake
...]]>
(Blackbox)https://gmatclub.com:443/forum/viewtopic.php?p=1932083#p1932083
Data Sufficiency (DS) | If a jar of candies is divided among 3 children, how many candies did https://gmatclub.com:443/forum/viewtopic.php?p=1932079#p1932079 Bunuel wrote:

If a jar of candies is divided among 3 children, how many candies did the child that received the fewest pieces receive?

(1) The two children that received the greatest number of pieces received a total of 13 pieces.
(2) The two children that received the fewest number of pieces received a total of 11 pieces.

Let the three children be$$A$$ ,$$B$$ &$$C$$ where candy distribution is$$A>B>C$$ . we need to find$$C$$ the lowest

Statement 1 implies that$$A+B = 13$$ . or$$A=13-B$$ .
Hence$$(A,B)$$ can be: (12,1),
...
]]>
Bunuel wrote:

If a jar of candies is divided among 3 children, how many candies did the child that received the fewest pieces receive?

(1) The two children that received the greatest number of pieces received a total of 13 pieces.
(2) The two children that received the fewest number of pieces received a total of 11 pieces.

Let the three children be$$A$$ ,$$B$$ &$$C$$ where candy distribution is$$A>B>C$$ . we need to find$$C$$ the lowest

Statement 1 implies that$$A+B = 13$$ . or$$A=13-B$$ .
Hence$$(A,B)$$ can be: (12,1),
...]]>
(niks18)https://gmatclub.com:443/forum/viewtopic.php?p=1932079#p1932079
Problem Solving (PS) | Re: John's front lawn is 1/3 the size of his back lawn. https://gmatclub.com:443/forum/viewtopic.php?p=1932068#p1932068
let back = B
front = 1/3B

done for front = 1/2*1/3B = 1/6B
done for back = 2/3B

combining workdone for front and back = 1/6 + 4/6 = 5/6B
what left to be done = (front + back) - (work done for front and back) = (1/3B + B) - 5/6B = 4/3B - 5/6B = 1/2B

ans. D?
]]>

let back = B
front = 1/3B

done for front = 1/2*1/3B = 1/6B
done for back = 2/3B

combining workdone for front and back = 1/6 + 4/6 = 5/6B
what left to be done = (front + back) - (work done for front and back) = (1/3B + B) - 5/6B = 4/3B - 5/6B = 1/2B

ans. D?]]>
(pannathat)https://gmatclub.com:443/forum/viewtopic.php?p=1932068#p1932068
Data Sufficiency (DS) | Re: If x and y are positive integers and 21x + 23y = z, what is the value https://gmatclub.com:443/forum/viewtopic.php?p=1932066#p1932066 While it's true that, when the variables can represent REAL NUMBERS, then there are infinitely many solutions to a system of 2 equations with 3 variables, the same cannot be said when we're the variables are limited to POSITIVE INTEGERS (as they are in the above question).

The test-makers LOVE to test this concept.

For more on this, watch the following video:
...
]]>
While it's true that, when the variables can represent REAL NUMBERS, then there are infinitely many solutions to a system of 2 equations with 3 variables, the same cannot be said when we're the variables are limited to POSITIVE INTEGERS (as they are in the above question).

The test-makers LOVE to test this concept.

For more on this, watch the following video:
...]]>
(GMATPrepNow)https://gmatclub.com:443/forum/viewtopic.php?p=1932066#p1932066
Problem Solving (PS) | The formula for the sum of squares of integer between 1 and n is n( https://gmatclub.com:443/forum/viewtopic.php?p=1932065#p1932065 MathRevolution wrote:

[GMAT math practice question]

The formula for the sum of squares of integer between 1 and n is n(n+1)(2n+1) / 6 = 1^2 + 2^2 + … + n^2. The is the value of 11^2 + 12^2 + … + 20^2?

A. 2470
B. 2475
C. 2480
D. 2485
E. 2490

Sum of squares from 1 to 20$$= \frac{20*21*41}{6} = 2870$$ (use the formula given)

Sum of squares from 1 to 10$$= \frac{10*11*21}{6} = 385$$

Hence sum of squares from 11 to 20$$=$$ Sum of squares from 1 to 20$$-$$ sum of squares from 1 to 10$$= 2870-385 = 2485$$

OptionD
...
]]>
MathRevolution wrote:

[GMAT math practice question]

The formula for the sum of squares of integer between 1 and n is n(n+1)(2n+1) / 6 = 1^2 + 2^2 + … + n^2. The is the value of 11^2 + 12^2 + … + 20^2?

A. 2470
B. 2475
C. 2480
D. 2485
E. 2490

Sum of squares from 1 to 20$$= \frac{20*21*41}{6} = 2870$$ (use the formula given)

Sum of squares from 1 to 10$$= \frac{10*11*21}{6} = 385$$

Hence sum of squares from 11 to 20$$=$$ Sum of squares from 1 to 20$$-$$ sum of squares from 1 to 10$$= 2870-385 = 2485$$

OptionD
...]]>
(niks18)https://gmatclub.com:443/forum/viewtopic.php?p=1932065#p1932065
Problem Solving (PS) | Re: If 3x^2 + 2x + 9 = 2x^2 + 9x + 3, what all the possible values of x ? https://gmatclub.com:443/forum/viewtopic.php?p=1932060#p1932060 nmargot wrote:

If 3x^2 + 2x + 9 = 2x^2 + 9x + 3, what all the possible values of x ?

A.-6 and -1
B.-6 and 1
C.-1 and 6
D.1 and 6
E.it cannot be determined from the information given.

Could someone expand on this pls?

$$3x^2 + 2x + 9 = 2x^2 + 9x + 3$$
=>$$x^2 - 7x + 6 = 0$$
=>$$x^2 - 6x - x + 6 = 0$$
=>$$x(x- 6) - (x - 6) = 0$$
=>$$(x- 6) (x + 1) = 0$$

So as ab =0 => either a =0 or b=0 or both a and b are = 0

So here we can say x-6 =0 or x-1 =0
=> x= 6 or x=1
=>
...
]]>
nmargot wrote:

If 3x^2 + 2x + 9 = 2x^2 + 9x + 3, what all the possible values of x ?

A.-6 and -1
B.-6 and 1
C.-1 and 6
D.1 and 6
E.it cannot be determined from the information given.

Could someone expand on this pls?

$$3x^2 + 2x + 9 = 2x^2 + 9x + 3$$
=>$$x^2 - 7x + 6 = 0$$
=>$$x^2 - 6x - x + 6 = 0$$
=>$$x(x- 6) - (x - 6) = 0$$
=>$$(x- 6) (x + 1) = 0$$

So as ab =0 => either a =0 or b=0 or both a and b are = 0

So here we can say x-6 =0 or x-1 =0
=> x= 6 or x=1
=>
...]]>
(Nikkb)https://gmatclub.com:443/forum/viewtopic.php?p=1932060#p1932060
Problem Solving (PS) | Re: Elizabeth is interested in dividing the rooms in the house among the f https://gmatclub.com:443/forum/viewtopic.php?p=1932051#p1932051 1. Add 2 to the current rooms & Reduce 1 from the initial number of members(Now Rooms/Members must be an integer)
2. Current Rooms/Members must not be an integer

Evaluating the answer options for the conditions
1. Both Options B and D are possible
2. All options possible except D

The answer option which satisfies both the conditions is Option B
]]>
1. Add 2 to the current rooms & Reduce 1 from the initial number of members(Now Rooms/Members must be an integer)
2. Current Rooms/Members must not be an integer

Evaluating the answer options for the conditions
1. Both Options B and D are possible
2. All options possible except D

The answer option which satisfies both the conditions is Option B]]>
(pushpitkc)https://gmatclub.com:443/forum/viewtopic.php?p=1932051#p1932051
DS Archive | Re: Tables Markers https://gmatclub.com:443/forum/viewtopic.php?p=1932048#p1932048 vitorpteixeira wrote:

Machines A and B each produce tablets at their respective constant rates. Machine A has produced 30 tablets when Machine B is turned on. Both machines continue to run until Machine B’s total production catches up to Machine A’s total production. How many tablets does Machine A produce in the time that it takes Machine B to catch up?

(1) Machine A’s rate is twice the difference between the rates of the two machines.

(2) The sum of Machine A’s rate and Machine B’s rate is five

...
]]>
vitorpteixeira wrote:

Machines A and B each produce tablets at their respective constant rates. Machine A has produced 30 tablets when Machine B is turned on. Both machines continue to run until Machine B’s total production catches up to Machine A’s total production. How many tablets does Machine A produce in the time that it takes Machine B to catch up?

(1) Machine A’s rate is twice the difference between the rates of the two machines.

(2) The sum of Machine A’s rate and Machine B’s rate is five

...]]>
(Bunuel)https://gmatclub.com:443/forum/viewtopic.php?p=1932048#p1932048
Problem Solving (PS) | In how many ways can digits 0, 2, 4, 7 be arranged to make a 4 digit https://gmatclub.com:443/forum/viewtopic.php?p=1932032#p1932032 fitzpratik wrote:

In how many ways can digits 0, 2, 4, 7 be arranged to make a 4 digit number without repetition

A. 12

B. 24

C. 18

D. 4

E. 28

Using FCP:

____ * ____ * ____ * ____

Conditions: 1) must be a 4-digit number; and 2) numbers from which to choose, no repetition: (0, 2, 4, 7)

First slot can be 2, 4 or 7 - there are threepossibilities

_3 _

Second slot also has only three possibilities; once 2, 4, or 7 is chosen, there are three numbers left

_3 * _3

Then, third slot, there are two numbers that
...
]]>
fitzpratik wrote:

In how many ways can digits 0, 2, 4, 7 be arranged to make a 4 digit number without repetition

A. 12

B. 24

C. 18

D. 4

E. 28

Using FCP:

____ * ____ * ____ * ____

Conditions: 1) must be a 4-digit number; and 2) numbers from which to choose, no repetition: (0, 2, 4, 7)

First slot can be 2, 4 or 7 - there are threepossibilities

_3 _

Second slot also has only three possibilities; once 2, 4, or 7 is chosen, there are three numbers left

_3 * _3

Then, third slot, there are two numbers that
...]]>
(genxer123)https://gmatclub.com:443/forum/viewtopic.php?p=1932032#p1932032
GMAT Club Tests | Re: M07-32 https://gmatclub.com:443/forum/viewtopic.php?p=1932027#p1932027 Bunuel, I have the same doubt as ArunpriyanJ

Appreciate if you can explain a bit further why we assume m=2 in your explanation.

Thanks!
]]>
Bunuel, I have the same doubt as ArunpriyanJ

Appreciate if you can explain a bit further why we assume m=2 in your explanation.

Thanks!]]>
(Simba9)https://gmatclub.com:443/forum/viewtopic.php?p=1932027#p1932027
PS Archive | speed and distance https://gmatclub.com:443/forum/viewtopic.php?p=1932024#p1932024
OPTION 1) 3 km/hr and 8 km/hr

2) 5 km/hr and 12 km/hr
3) 4 km/hr and 11 km/hr
4) 3 km/hr and 12 km/hr
5) 4 km/hr and 10 km/hr
]]>

OPTION 1) 3 km/hr and 8 km/hr

2) 5 km/hr and 12 km/hr
3) 4 km/hr and 11 km/hr
4) 3 km/hr and 12 km/hr
5) 4 km/hr and 10 km/hr]]>
(saidurr)https://gmatclub.com:443/forum/viewtopic.php?p=1932024#p1932024
Problem Solving (PS) | What is the Greatest Common Factor (GCF) of 18x^8y^(20) and 24x^12y^15 https://gmatclub.com:443/forum/viewtopic.php?p=1932015#p1932015 Gnpth wrote:

What is the Greatest Common Factor (GCF) of $$18x^8y^{(20)}$$ and $$24x^{(12)}y^{(15)}$$?

A. $$3x^4y^5$$

B. $$6x^4y^5$$

C. $$3x^8y^{(15)}$$

D. $$6x^8y^{(15)}$$

E. $$72x^{(12)}y^{(20)}$$

To find GCF, find the prime factorization of both expressions.

$$18x^8y^{(20)}$$ =
$$2 * 3 * 3 * x^8 * y^{(20)}$$
$$24x^{(12)}y^{(15)}$$ =
$$2 * 2 * 2 * 3 * x^{(12)} * y^{(15)}$$
Find all the factors they have in common, "to the lowest power."
...
]]>
Gnpth wrote:

What is the Greatest Common Factor (GCF) of $$18x^8y^{(20)}$$ and $$24x^{(12)}y^{(15)}$$?

A. $$3x^4y^5$$

B. $$6x^4y^5$$

C. $$3x^8y^{(15)}$$

D. $$6x^8y^{(15)}$$

E. $$72x^{(12)}y^{(20)}$$

To find GCF, find the prime factorization of both expressions.

$$18x^8y^{(20)}$$ =
$$2 * 3 * 3 * x^8 * y^{(20)}$$
$$24x^{(12)}y^{(15)}$$ =
$$2 * 2 * 2 * 3 * x^{(12)} * y^{(15)}$$
Find all the factors they have in common, "to the lowest power."
...]]>
(genxer123)https://gmatclub.com:443/forum/viewtopic.php?p=1932015#p1932015
Problem Solving (PS) | Re: A set P = {1, 2, 3, 4, 5} and set Q = {1, 2, 3, 4, 5, 6, 7} https://gmatclub.com:443/forum/viewtopic.php?p=1932013#p1932013 gmatdemolisher1234 wrote:

There are total of 8 (p,q) pairs possible so that the absolute difference between the two numbers to be 2: (1, 3), (2, 4), (3, 5), (3, 1), (4, 6), (4, 2), (5, 7), (5, 3) (first # is chosen from set P and second # is chosen from set Q). 4 pairs contain the number 3 in it, so P=4/8=1/2.

Bunuel - according to my inference from the question we are not specifically told to select first no. from set P and the second no. from set Q. Why are we specifically following the order ?
...
]]>
gmatdemolisher1234 wrote:

There are total of 8 (p,q) pairs possible so that the absolute difference between the two numbers to be 2: (1, 3), (2, 4), (3, 5), (3, 1), (4, 6), (4, 2), (5, 7), (5, 3) (first # is chosen from set P and second # is chosen from set Q). 4 pairs contain the number 3 in it, so P=4/8=1/2.

Bunuel - according to my inference from the question we are not specifically told to select first no. from set P and the second no. from set Q. Why are we specifically following the order ?
...]]>
(Bunuel)https://gmatclub.com:443/forum/viewtopic.php?p=1932013#p1932013
Data Sufficiency (DS) | Re: Is xy< 10? 1) x<2 2) y<5 https://gmatclub.com:443/forum/viewtopic.php?p=1932005#p1932005 MathRevolution wrote:

Is xy < 10?

1) x < 2
2) y < 5

Target question: Is xy< 10?

Statement 1: x < 2
Since there's no information about y, this statement is not sufficient.
There are several values of x and y that satisfy statement 1. Here are two:
Case a x = 1 and y = 1, which means xy = (1)(1) = 1. So,xy < 10
Case b x = 1 and y = 20, which means xy = (1)(20) = 1. So,xy > 10
Since we cannot answer the target
...
]]>
MathRevolution wrote:

Is xy < 10?

1) x < 2
2) y < 5

Target question: Is xy< 10?

Statement 1: x < 2
Since there's no information about y, this statement is not sufficient.
There are several values of x and y that satisfy statement 1. Here are two:
Case a x = 1 and y = 1, which means xy = (1)(1) = 1. So,xy < 10
Case b x = 1 and y = 20, which means xy = (1)(20) = 1. So,xy > 10
Since we cannot answer the target
...]]>
(GMATPrepNow)https://gmatclub.com:443/forum/viewtopic.php?p=1932005#p1932005
Problem Solving (PS) | Re: Machine A and machine B are each used to manufacture 660 https://gmatclub.com:443/forum/viewtopic.php?p=1932001#p1932001 soodia wrote:

Bunuel wrote:
zisis wrote:
Machine A and machine B are each used to manufacture 660 sprockets. It takes machine A 10 hours longer to produce 660 sprockets than machine B. Machine B produces 10 percent more sprockets per hour than machine A. How many sprockets per hour does machine A produces?

6
6.6
60
100
110

book give a backsolving solution which I am not a big fan of...........please explain method...

Let time needed for machine A to produce 660 sprockets be$$a$$ hours, then the rate of machine A would be$$rate_A=\frac{job \ done}{time}$$
...
]]> soodia wrote:

Bunuel wrote:
zisis wrote:
Machine A and machine B are each used to manufacture 660 sprockets. It takes machine A 10 hours longer to produce 660 sprockets than machine B. Machine B produces 10 percent more sprockets per hour than machine A. How many sprockets per hour does machine A produces?

6
6.6
60
100
110

book give a backsolving solution which I am not a big fan of...........please explain method...

Let time needed for machine A to produce 660 sprockets be$$a$$ hours, then the rate of machine A would be$$rate_A=\frac{job \ done}{time}$$
...]]> (Bunuel)https://gmatclub.com:443/forum/viewtopic.php?p=1932001#p1932001 Quantitative | Re: How to score 50 in quant https://gmatclub.com:443/forum/viewtopic.php?p=1931988#p1931988
generally 5-8 wrong answer can be accommodated to score Q50.
Try to solve each questions but if any question is taking more than 3 min then skip
most important thing is to read explanation of all the questions
]]>

generally 5-8 wrong answer can be accommodated to score Q50.
Try to solve each questions but if any question is taking more than 3 min then skip
most important thing is to read explanation of all the questions]]>
(mbaaspirant80)https://gmatclub.com:443/forum/viewtopic.php?p=1931988#p1931988
Data Sufficiency (DS) | Re: $150 in prize money is going to be split among 6 contestants https://gmatclub.com:443/forum/viewtopic.php?p=1931987#p1931987 Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. ]]> Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.]]> (bumpbot)https://gmatclub.com:443/forum/viewtopic.php?p=1931987#p1931987 Data Sufficiency (DS) | Re: If$1,000 is deposited in a certain bank account and remains in the https://gmatclub.com:443/forum/viewtopic.php?p=1931986#p1931986 Th3Ap3xPr3dator wrote:

Dear Experts Bunuel, VeritasPrepKarishma,

In case of inequalities, can we take square roots on both sides?

We can raise both parts of an inequality to an even power if we know that both parts of an inequality are non-negative (the same for taking an even root of both sides of an inequality).

Check for more here:Manipulating Inequalities (adding, subtracting, squaring etc.).

Hope it helps.
...
]]> Th3Ap3xPr3dator wrote:

Dear Experts Bunuel, VeritasPrepKarishma,

In case of inequalities, can we take square roots on both sides?

We can raise both parts of an inequality to an even power if we know that both parts of an inequality are non-negative (the same for taking an even root of both sides of an inequality).

Check for more here:Manipulating Inequalities (adding, subtracting, squaring etc.).

Hope it helps.
...]]> (Bunuel)https://gmatclub.com:443/forum/viewtopic.php?p=1931986#p1931986 Data Sufficiency (DS) | Re: Joan spent $10 to buy at least one piece each of apples a https://gmatclub.com:443/forum/viewtopic.php?p=1931981#p1931981 Mo2men wrote: Dear Brent, Based on what you stated, it should be case i. It is the only case that orange greater than$6 and be able to divide by $2 and hence gives 1 apple. Good catch - thanks! I've edited my response accordingly. Cheers, Brent ]]> Mo2men wrote: Dear Brent, Based on what you stated, it should be case i. It is the only case that orange greater than$6 and be able to divide by \$2 and hence gives 1 apple.

Good catch - thanks!
I've edited my response accordingly.

Cheers,
Brent]]>
(GMATPrepNow)https://gmatclub.com:443/forum/viewtopic.php?p=1931981#p1931981
Data Sufficiency (DS) | Re: If x is a positive integer, what is the units digit of 3x? https://gmatclub.com:443/forum/viewtopic.php?p=1931974#p1931974 siddhans wrote:

If x is a positive integer, what is the units digit of 3x?

(1) x = 10k^2 + 1, where k is a positive integer.
(2) The units digit of x^2 is 1.

St 1

This statement basically tells us that the units digit of X will always be 1 because no matter what K is, and K must be a positive integer, 10k^2 will always be a multiple of 10 and thus have a units digit of 0. If this is true then x will always have a units digit of 1 and if x always has a units digit of 1 then the units digit of 3x will always
...
]]>
siddhans wrote:

If x is a positive integer, what is the units digit of 3x?

(1) x = 10k^2 + 1, where k is a positive integer.
(2) The units digit of x^2 is 1.

St 1

This statement basically tells us that the units digit of X will always be 1 because no matter what K is, and K must be a positive integer, 10k^2 will always be a multiple of 10 and thus have a units digit of 0. If this is true then x will always have a units digit of 1 and if x always has a units digit of 1 then the units digit of 3x will always
...]]>
(Nunuboy1994)https://gmatclub.com:443/forum/viewtopic.php?p=1931974#p1931974
GMAT Club Tests | Re: M20-09 https://gmatclub.com:443/forum/viewtopic.php?p=1931965#p1931965 Hence D
Remember + is used when there are more ways of doing the same task in different ways.
and * is used when the task at hand is not complete .
Hope this helps
]]>
Hence D
Remember + is used when there are more ways of doing the same task in different ways.
and * is used when the task at hand is not complete .
Hope this helps]]>
Problem Solving (PS) | Re: How many positive integers less than 200 are there such that they are https://gmatclub.com:443/forum/viewtopic.php?p=1931951#p1931951
Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.]]>
(bumpbot)https://gmatclub.com:443/forum/viewtopic.php?p=1931951#p1931951
Problem Solving (PS) | Re: Which of the following is the largest? https://gmatclub.com:443/forum/viewtopic.php?p=1931945#p1931945 VeritasPrepKarishma wrote:

mau5 wrote:
Which of the following is the largest?

(A) $$2^{27.3}$$

(B) $$3^{18.2}$$

(C) $$5^{11.1}$$

(D)$$7^{9.1}$$

(E)$$11^{5.1}$$

Fresh from Manhattan Prep (Challenge of the week)

First look for some commonality - either power or base.
I see that 27.3 is 3*9.1 and 18.2 is 2*9.1.
So
(A)$$2^{27.3} = 8^{9.1}$$

(B)$$3^{18.2} = 9^{9.1}$$

(D)$$7^{9.1}$$
Out of (A), (B) and (D), (B) is the largest.

We can easily compare$$(C) 5^{11}$$ with$$(E) 11^{5}$$ . Out of a^b and b^a, greater is usually the one with
...
]]> VeritasPrepKarishma wrote:

mau5 wrote:
Which of the following is the largest?

(A) $$2^{27.3}$$

(B) $$3^{18.2}$$

(C) $$5^{11.1}$$

(D)$$7^{9.1}$$

(E)$$11^{5.1}$$

Fresh from Manhattan Prep (Challenge of the week)

First look for some commonality - either power or base.
I see that 27.3 is 3*9.1 and 18.2 is 2*9.1.
So
(A)$$2^{27.3} = 8^{9.1}$$

(B)$$3^{18.2} = 9^{9.1}$$

(D)$$7^{9.1}$$
Out of (A), (B) and (D), (B) is the largest.

We can easily compare$$(C) 5^{11}$$ with$$(E) 11^{5}$$ . Out of a^b and b^a, greater is usually the one with
...]]> (VeritasPrepKarishma)https://gmatclub.com:443/forum/viewtopic.php?p=1931945#p1931945 Problem Solving (PS) | Re: The numbers of pizza slices that are sold in Joey's Pizza are only in https://gmatclub.com:443/forum/viewtopic.php?p=1931941#p1931941
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Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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(bumpbot)https://gmatclub.com:443/forum/viewtopic.php?p=1931941#p1931941
GMAT Club Tests | Re: M19-36 https://gmatclub.com:443/forum/viewtopic.php?p=1931926#p1931926 -X
CROSS MULTIPLY
= - X × 0 > X + 1
= 0 > × + 1
]]>
-X
CROSS MULTIPLY
= - X × 0 > X + 1
= 0 > × + 1]]>
(az buck)https://gmatclub.com:443/forum/viewtopic.php?p=1931926#p1931926
Problem Solving (PS) | Re: How many integers from 0 to 50, inclusive, have a remainder https://gmatclub.com:443/forum/viewtopic.php?p=1931920#p1931920
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]]>

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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(bumpbot)https://gmatclub.com:443/forum/viewtopic.php?p=1931920#p1931920
Problem Solving (PS) | Re: The music class consists of 4 girls and 7 boys. How many way https://gmatclub.com:443/forum/viewtopic.php?p=1931918#p1931918 4 girls
7 boys
total = 11
3 is the number of group to be formed

using this formula: n! (n-r!)r! therefore 11! - 7!
- (11-3!)3! (7-3!)3!

...
]]>
4 girls
7 boys
total = 11
3 is the number of group to be formed

using this formula: n! (n-r!)r! therefore 11! - 7!
- (11-3!)3! (7-3!)3!

...]]>
(az buck)https://gmatclub.com:443/forum/viewtopic.php?p=1931918#p1931918
Problem Solving (PS) | Re: For integers x, y, and z, if ((2^x)^y)^z = 131072 which of https://gmatclub.com:443/forum/viewtopic.php?p=1931912#p1931912
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Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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(bumpbot)https://gmatclub.com:443/forum/viewtopic.php?p=1931912#p1931912
Problem Solving (PS) | Re: Find the sum of the sum of even divisors of 96 and the sum of odd divi https://gmatclub.com:443/forum/viewtopic.php?p=1931911#p1931911 krish182 wrote:

Bunuel