It is currently Wed May 23, 2012 5:33 am




   Post new topic Reply to topic      [ 97 posts ]  Bookmark and Share Oldest Best Reply Go to page Previous  1, 2, 3, 4, 5
Author Message
TAGS:
New postPosted: Fri Oct 13, 2006 9:09 pm 
Offline
Manager
Manager
User avatar

Joined: Sat Jul 08, 2006
Posts: 92
Followers: 1

Kudos (?): 0 (0), given: 0

Artemov wrote:
The differential distance of 2 km is being covered in 1hr. So, 0.2 km would be covered in 0.1 hr. And the deer will travel 1 km in 0.1 hr @ 10km/hr.


I would choose your solution if you would explain further.
I understand the differential distance being covered in 1hr, I understand that 0.2km will be covered in 0.1hr.

Notwithstanding the fact that you got the right answer, I don't understand why we are using 0.1hr to arrive at the distance traveled by the deer before it is caught when, clearly, the lion took that time to arrive at the deer's initial position. Shouldn't the time we use be greater?


  Profile  
 
New postPosted: Mon Oct 16, 2006 3:45 am 
Offline
Senior Manager
Senior Manager

Joined: Thu Oct 05, 2006
Posts: 286
Followers: 1

Kudos (?): 1 (0), given: 0

GMAT Tests User
i tried this way.
when taking both choices i.e., x>2y and x<y+2

we can write, 2y<x<y+2
so x lies in between 2y and y+2 for all x,y>0

from 2y<x<y+2
implies 2y<y+2
impliws y<2

hence we can answer the question that y is not more than 2.
hencechoice c.

any comments plz??



ywilfred wrote:
If x and y are positive, is y > 2?
1. x > 2y
2. x < y + 2


From statement (1), we have x > 2y => y < x/2. So y can take on various positive values dependign on what postive values x takes on. Statement (1) is therefore not sufficient.

From statement (2), we have x < y + 2 => x - y < 2. So now x and y can take on sets of value, limited by the inequality above. If x,y = 3,2, then x - y < 2 but y is not greater than 2. However, if x,y = 10,9, then x -y < 2 but y is now greater than 2. So statement (2) insufficient.

Using both statement (1) and statement (2), we have y < x/2 and x-y < 2. Now, we'll test for possible x,y pairs that satisfies both inequalities.

If x = 10, y < 5. (say, y = 4), then x-y = 10-4 > 2. So x cannot be any value larger than 10.

If x = 5, y < 2.5 (say y = 2.4), then x-y = 2.6 > 2. So x cannot be any value larger than 5.

If x = 3, y < 1.5 (say y = 1.4), then x-y = 1.6 < 2. So x can be 3 and below.

If x = 4, y < 2 (say y = 1.9), then x-y = 2.1 > 2. So x cannot be 4 and above.

If x = 3.59, y < 1.795 (say y = 1.69) then x-y = 1.9 < 2. So Maximum value of x would be approximately 3.59 and y would be less than 2 for all values of x 3.59 and below.

The answer is therefore C.

Note: The question does not say x and y are integers, so we must also consider decimals (or fractions)


  Profile  
 
New postPosted: Mon Oct 16, 2006 9:24 pm 
Offline
Manager
Manager

Status: Post MBA, working in the area of Development Finance
Joined: Mon Oct 09, 2006
Posts: 180
Location: Africa
Followers: 1

Kudos (?): 1 (0), given: 1

Rayn wrote:
Artemov wrote:
The differential distance of 2 km is being covered in 1hr. So, 0.2 km would be covered in 0.1 hr. And the deer will travel 1 km in 0.1 hr @ 10km/hr.


I would choose your solution if you would explain further.
I understand the differential distance being covered in 1hr, I understand that 0.2km will be covered in 0.1hr.

Notwithstanding the fact that you got the right answer, I don't understand why we are using 0.1hr to arrive at the distance traveled by the deer before it is caught when, clearly, the lion took that time to arrive at the deer's initial position. Shouldn't the time we use be greater?


A leopard spots a deer from a distance of 200 meters. As the leopard starts chasing the deer, the deer also starts running. Given that the speed of the deer is 10 km/h and that of the leopard is 12 km/h, how far would have the deer run before it is caught?

How much distance would the deer cover in 0.1 hr => 1 km
How much distance would the leopard cover in 0.1 hr => 1.2 km
At the end of 0.1 hr the lead of 200 mtrs would have been covered.


  Profile  
 
New postPosted: Sun Dec 24, 2006 10:59 pm 
Offline
VP
VP
User avatar

Joined: Sun Feb 26, 2006
Posts: 1093
Followers: 2

Kudos (?): 19 (0), given: 0

GMAT Tests User
ywilfred wrote:
Is sqrt(x-5)^2 = 5-x?

1) -x|x| > 0
2) 5-x > 0


sqrt(x-5)^2 is really just (x-5). So what the question is asking is whether x-5 = 5-x => x = 10. If either statement tells us if x is 10 or any other particular value, then it is sufficient.

From statement (1), for -x|x| to be greater than zero, x must be negative. And if x is negative, then it can't be 10. Therefore, statement (1) is sufficient.

From statement (2), we have 5 - x > 0 => x < 5. We know x has to be less than 5, so x cannot be 10. Statement (2) alone is sufficient as well.

The answer is therefore D.


i do this way.

the question is "Is sqrt(x-5)^2 = 5-x?" or "is x = 5?".

from 1) we know x is -ve. so x is not equal to 5. suff.
from 2) 5>x. so x is not equal to 5. suff.

so D......


  Profile  
 
New postPosted: Thu Jan 18, 2007 8:50 pm 
Offline
Intern
Intern

Joined: Sat Jul 23, 2005
Posts: 8
Followers: 0

Kudos (?): 0 (0), given: 0

ywilfred wrote:
If x and y are non-zero integers, is x ^y < y ^x

1. x = y^2
2. y > 2


For such questions, the statement is sufficient if we can answer a yes or a no to the questions "Is x^y < y^x".

Using statement (1), we have x = y^2. So if y = 1, x = 1. then x^y is not less than y^x. However, if y = 3, x = 9. Then x^y is less than x^y. So we can't answer the question posed and statement (1) is therefore not sufficient.

Using statement (2), we have y > 2, but we have no values of x to work with. So we still can't answer the question. Statement (2) is therefore not sufficient.

Using both statement (1) and statement (2), we know y is 3 and above. For all values of y that is 3 and above, y^x is always less then x^y. So we can now answer the question - "Is x^y < y^x ?" The answer is no.

The answer therefore is C.


I agree with the answer C but disagree with the last statement - in bold. Indeed x^y < y^x


  Profile  
 
New postPosted: Fri Jan 19, 2007 4:17 am 
Offline
Intern
Intern

Joined: Thu Jan 18, 2007
Posts: 2
Location: India
Followers: 0

Kudos (?): 0 (0), given: 0

ywilfred wrote:
What is the least value of the three digit integer y?

1) the sum of the three digits is 5
2) y is divisible by 5


From statement (1), we're told the sum of the three digits is 5. The least value will therefore be in the range of 100+. 104 should therefore be the smallest number. Statement (1) is sufficient.

From statement (2), were told y is divisible by 5. So the last digit should be either 0 or 5. So the number can either be 100 or 105. Since we're asked for the least value, therefore y has to be 100. Statement (2) is therefore sufficient.

The answer should be D.


For Statement (1) d least value should be -995 as it isnt mentioned dat the 3 digit number is positive.

For Statement (2) The least value is 100.

What answer choice should we choose in this case? E? or is it D?


  Profile  
 
New postPosted: Sat Jan 20, 2007 2:53 pm 
Offline
Intern
Intern

Joined: Sat Jul 23, 2005
Posts: 8
Followers: 0

Kudos (?): 0 (0), given: 0

dipidha wrote:
ywilfred wrote:
What is the least value of the three digit integer y?

1) the sum of the three digits is 5
2) y is divisible by 5


From statement (1), we're told the sum of the three digits is 5. The least value will therefore be in the range of 100+. 104 should therefore be the smallest number. Statement (1) is sufficient.

From statement (2), were told y is divisible by 5. So the last digit should be either 0 or 5. So the number can either be 100 or 105. Since we're asked for the least value, therefore y has to be 100. Statement (2) is therefore sufficient.

The answer should be D.


For Statement (1) d least value should be -995 as it isnt mentioned dat the 3 digit number is positive.

For Statement (2) The least value is 100.

What answer choice should we choose in this case? E? or is it D?


well that is a good point. How can you associate the -ve sign to first 9 and positive sign to second 9. I dont agree with that. May be -500 is the lowest 3 digit number which adds to 5.
Also for second statement may be -995 is the right one.
However the answer still remains as D


  Profile  
 
New postPosted: Mon Jan 22, 2007 11:19 am 
Offline
CEO
CEO
User avatar

Joined: Mon Jan 03, 2005
Posts: 2603
Followers: 6

Kudos (?): 129 (0), given: 0

GMAT Tests User
Good observations. I would say that this question is not well designed. It may be better if it had said "positive integers". The other thing though, is that from my experience, for GMAT questions that have D as the answer, the two options should lead to the same result.

_________________
Keep on asking, and it will be given you;
keep on seeking, and you will find;
keep on knocking, and it will be opened to you.


  Profile  
 
New postPosted: Mon Jan 22, 2007 9:46 pm 
Offline
Intern
Intern

Joined: Thu Jan 18, 2007
Posts: 2
Location: India
Followers: 0

Kudos (?): 0 (0), given: 0

thats exactly my doubt! how do v say its D wen d 2 ans differ??


  Profile  
 
New postPosted: Sun Apr 08, 2007 7:58 am 
Offline
Director
Director
User avatar

Joined: Wed Aug 09, 2006
Posts: 595
Followers: 2

Kudos (?): 18 (0), given: 0

GMAT Tests User
ywilfred wrote:
I'll start with this one today.

A slot machine in a Las Vegas casino has an average profit of $600 for each 8 hours shift for the five days sunday through thrusday , inclusive . If the average per shift profit on Friday and saturday is 25% greater than on the other days of the week and the slot machine is in operation every hour of everyday, wheat is the total weekly profit that the casino makes fromt he slot machine?
$4500
$9000
$13500
$15500
$27000


This questions tests on your ability to breakdown the long passage, assimilate the information and turn them into equations to work on.

We're told the slot machines has:

1. Average profit/shift = $600 for Sunday - Thursday
2. Average profit/shift = 25% greater on Friday and Saturday
3. Slot machine is in operation every hour of everyday

Since we know the machine works non stop for 24 hours each day, and there's a 8 hour shift, so each day there's 24/8 = 3 shifts
So, from Sunday to Thursday, there's a total of 5*3 = 15 shifts
So the total profit from the 5 days = 600*15 = $9000

We also know from the question, that the average profit/shift = (125/100)*600 = $750
And for the two days, we have 2*3 = 6 shifts
Therefore, the total profit for Friday and Saturday = 750*6 = $4500

So all we need to do now is to add up the two total profits to give the total weekly profit. That sum is $9000+$4500 = $13,500.
The answer is therefore, C.


Hi ywilfred,
I have a doubt.
We have already calculated the profit for 5 days as 9000$ including the thursaday and Fri . This 9000$ profit includes the 600$/shift profit on thursday and Frid. Since thur and fri have 25% more profit /shift which is 750$/shift x 6 = 4500$. But out of this 4500$ 3600$ have already been taken into account. So I think the effective profit is $9000 + (4500 - 3600) = 9000 + 900 = 9900$. Adding 4500 means we are adding the profit twice. Even though there is no option in answer choice, but my reasoning says this. Could you please suggest where am I wrong.


  Profile  
 
New postPosted: Wed Oct 10, 2007 8:03 am 
Offline
Director
Director
User avatar

Joined: Fri Sep 14, 2007
Posts: 912
Schools: Kellogg '10
Followers: 5

Kudos (?): 78 (0), given: 15

GMAT Tests User
Not sure if anyone will find this helpful, but I've pasted all of the questions from this thread into a single Word document.

This will be my airplane study guide.

Thanks so much to ywilfred for putting this thread together.


Attachments:
GMAT Practice Questions.doc [86.5 KiB]
Downloaded 158 times
To download please login or register as a user

  Profile  
 
New postPosted: Wed Oct 10, 2007 8:23 am 
Offline
Senior Manager
Senior Manager
User avatar

Joined: Mon Aug 27, 2007
Posts: 276
Followers: 1

Kudos (?): 6 (0), given: 0

GMAT Tests User
Artemov wrote:
ywilfred wrote:
A leopard spots a deer from a distance of 200 meters. As the leopard starts chasing the deer, the deer also starts running. Given that the speed of the deer is 10 km/h and that of the leopard is 12 km/h, how far would have the deer run before it is caught?

A. 3 km
B. 4 km
C. 2 km
D. 1 km
E. 5 km


This question test the ability to recall the Distance-Speed-Time formula, and also to manipulate the question to formulate the equation for solving the question (by use of algebra).
In such Distance-Speed-Time question (which involves A catching up with B), there's normally one quantity that's similar.
Also, remember to make sure that your units match, otherwise your answer will not come out right.

We know from the passage:
1. The Leopard and the Deer are 200 meters apart = 0.2 km
2. THe speed of the Leopard = 12km/hr
3. The speed of the Deer = 10 km/hr

Let's assume that the Deer has travelled x km before it is caught. The Leopard would then have to travel (x+0.2)km. There is one quantity that is the same here, that is the time taken for the deer to travel that x km, and for the Leopard to travel (x+0.2km).

Since we know that Time = Distance/Speed, we can equate:

Time taken by Deer to travel x km = Time taken by Leopard to travel (x+0.2) km
x/10 = (x+0.2)/12
12x = 10x + 2
2x = 2
x = 1 km

The answer is therefore, D.




The differential distance of 2 km is being covered in 1hr. So, 0.2 km would be covered in 0.1 hr. And the deer will travel 1 km in 0.1 hr @ 10km/hr.


Have the same as Artemov's:

10t+0.2=12t
t=0.1

0.1*10=1 km


  Profile  
 
  Re: Beginners Forum (Re-worked questions) [#permalink]
New postPosted: Wed Jul 08, 2009 11:36 am 
Offline
Manager
Manager

Joined: Tue Apr 07, 2009
Posts: 148
Followers: 1

Kudos (?): 7 (0), given: 3

Quote:
If X and Y are integers and Y =/x+3/ + /4-x/, does y equal 7?

1. x < 4
2. x > -3

Using statement (1), we know x can be 3 and below. This will give us a number of y values, so statement (1) is not sufficient.

Using statement (2), the same problem exists. x can be any value above -3 and this will give us a number of y values. So statement (2) is not sufficient.

Using both statements, we can get the inequality: -3 < x < 4.

Now x will have to take on either values -2, -1, 0, 1, 2 or 3.

If x = 0, y = 7.
If x = 1, y = 7
If x = 2, y = 7
If x = 3, y = 7
If x = -1, y = 7
If x= -2, y = 7

So using both statements will limit values of x that always result in y taking on the value of 7.

The answer is therefore C.


why isnt the answer B ? For all values I get only 7 , I must be overlooking something, help !


  Profile  
 
  Re: [#permalink]
New postPosted: Mon Mar 08, 2010 5:45 pm 
Offline
Manager
Manager

Joined: Mon Feb 15, 2010
Posts: 69
Location: Tokyo
Schools: Insead
Followers: 1

Kudos (?): 9 (0), given: 15

GMAT ToolKit User
Rubashov1 wrote:
Not sure if anyone will find this helpful, but I've pasted all of the questions from this thread into a single Word document.

This will be my airplane study guide.

Thanks so much to ywilfred for putting this thread together.


nice! very helpful!


  Profile  
 
  Re: [#permalink]
New postPosted: Mon May 03, 2010 9:18 am 
Offline
Intern
Intern

Joined: Sat May 01, 2010
Posts: 4
Followers: 0

Kudos (?): 0 (0), given: 0

Himalayan wrote:
ywilfred wrote:
Is sqrt(x-5)^2 = 5-x?

1) -x|x| > 0
2) 5-x > 0


sqrt(x-5)^2 is really just (x-5). So what the question is asking is whether x-5 = 5-x => x = 10. If either statement tells us if x is 10 or any other particular value, then it is sufficient.

From statement (1), for -x|x| to be greater than zero, x must be negative. And if x is negative, then it can't be 10. Therefore, statement (1) is sufficient.

From statement (2), we have 5 - x > 0 => x < 5. We know x has to be less than 5, so x cannot be 10. Statement (2) alone is sufficient as well.

The answer is therefore D.


i do this way.

the question is "Is sqrt(x-5)^2 = 5-x?" or "is x = 5?".

from 1) we know x is -ve. so x is not equal to 5. suff.
from 2) 5>x. so x is not equal to 5. suff.

so D......




I agree with the second point of view of Himalayan.
I can't really understand how the first one is correct.
x-5 = 5-x => x = 10. <- how on earth is this right???

quite helpful post nevertheless
there are some mistakes though...


  Profile  
 
  Re: Beginners Forum (Re-worked questions) [#permalink]
New postPosted: Wed Feb 01, 2012 11:13 am 
Offline
Intern
Intern

Joined: Wed Aug 25, 2010
Posts: 16
Followers: 0

Kudos (?): 0 (0), given: 11

hi ,
just would like to know as to how many problems are there in this section? as of now i have seen 19 questions in this page 1. request to let me know


thanks
eshwar

_________________
regards
eshwar


  Profile  
 
  Re: Re: [#permalink]
New postPosted: Wed Feb 01, 2012 11:25 am 
Offline
Manager
Manager

Joined: Fri Jan 06, 2012
Posts: 86
Followers: 0

Kudos (?): 8 (0), given: 20

Scrat wrote:
Rubashov1 wrote:
Not sure if anyone will find this helpful, but I've pasted all of the questions from this thread into a single Word document.

This will be my airplane study guide.

Thanks so much to ywilfred for putting this thread together.


nice! very helpful!


+1, Thanks for your efforts!


  Profile  
 
Online
gmatclubot
Display posts from previous:  Sort by  

GMAT Resources

Best GMAT Discussions

GMATPrep PS Question Bank by Anonym48
GMATPrep DS Question Bank by Anonym46
Valuable Collection of Percentage Questions (PS/DS) by MBAhereIcome23
GMAT MATH BOOK in downloadable PDF format by Bunuel18
My comprehensive Quant Flashcards! by miguelmick13

Quant Expert Advice

Post new topic Reply to topic  [ 97 posts ]  Go to page Previous  1, 2, 3, 4, 5

 Similar topics   Author   Replies   Views   Last post 
Beginner's Forum Question

in GMAT Problem Solving (PS)

mmcooley33

4

604

Sat Dec 11, 2010 11:52 pm

Beginner

in GMAT

vinoth79

2

671

Fri Jul 18, 2008 2:03 am

Beginner

in GMAT

vinoth79

1

635

Fri Jul 18, 2008 2:03 am

Here's another one I picked off the Beginners forum. It's a

in GMAT Problem Solving (PS)

ywilfred

8

536

Thu Jun 23, 2005 1:25 am

CR- reworks

in GMAT Critical Reasoning (CR)

stevegt

5

291

Mon Jul 02, 2007 11:46 pm





Who is online

Users browsing this forum: No registered users and 1 guest


Search for:
Jump to:





[ Mobile Version ] GMAT Club MBA Forum Home | About | Privacy Policy | Terms and Conditions | GMAT Club Rules | Contact | Sitemap
Powered by phpBB © phpBB Group and phpBB SEO
Kindly note that GMAT (C) is a registered trademark of the Graduate Management Admission Council, and this site has neither been reviewed nor endorsed by GMAC.