GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 20 Oct 2019, 06:56 GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.  The Ultimate Q51 Guide [Expert Level]

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

1
NandishSS wrote:
MathRevolution wrote:
This is a 50-51 level question

(ex 7) *(integer) What is the greatest common divisor of positive integers n and m?
1) n=1
2) m=n+1
There are 2 variables in the original condition (m, n). In order to match the number of variables and the number of equations, we need 2 equations. Hence, there is a high chance that C is the correct answer. Using 1) and 2), C is the correct answer. However, we have to utilize the common mistake type 4(B) since it is an integer question. The correct answer is D.

MathRevolution Could pls elaborate this que how the ans is D

1) if a certain number is 1, the greatest common divisor is always 1
2) in case of consecutive numbers, the greatest common divisor is also 1. Hence, the conditions are sufficient, and the correct answer is D.
_________________
Senior Manager  Joined: 31 Mar 2016
Posts: 375
Location: India
Concentration: Operations, Finance
GMAT 1: 670 Q48 V34 GPA: 3.8
WE: Operations (Commercial Banking)
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

Jin,

Most of the tough questions i got today were from co-ordinate geometry. Surprisingly the question pool threw no questions such divisbility etc. The geometry questions on GMAT were much more tougher than we see on any prep material.
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

Below is a 50-51 level questions. It involves ignoring square in inequality.
If p^4q^7r^5<0, is pqr<0?
1) q>0
2) r<0
If we modify the original condition and the question, we If qr<0, is pqr<0? and p>0? However, since we do not have data for p, the correct answer is E.
_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

Below is CMT4 quesiton
When p and t are positive integers and p is a factor of t, is t/p an even?
1) t is an even
2) p+t is an odd

There are 2 variables in the original condition, hence, there is a high chance that C is the correct answer. Using 1) & 2), C is the correct answer. However, since this is a key question, if we apply CMT 4(A), using condition 2), the answer becomes yes and the condition is sufficient. Thus, the correct answer is B.
_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

Senthil7 wrote:
Jin,

Most of the tough questions i got today were from co-ordinate geometry. Surprisingly the question pool threw no questions such divisbility etc. The geometry questions on GMAT were much more tougher than we see on any prep material.

Hi Senthil 7,

In fact, co-ordinate geometry questions given are not that difficult. The distance between two spots, areas of triangles, squares, parallelograms, questions to solve with the mistake type 4(A) of DS are given. It may seem difficult when you actually draw, but it is not that difficult.

Best regards,

Jin
Math Revolution
_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

If 5-digit positive integer ab,aba is divided by 3, what is the remainder?
1) a=3
2) b=1
We can modify the original condition and the question. If we divide ab and abc by 3, the remainder is same as a+b+a+b+a=3a+2b divided 3. Hence, since 3a is same as 3, we only have to know 2b. Thus, the correct answer is B.
_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

There are some 50-51 level geometry questions.
A triangle has 3 sides x, y, z such that x<y<z. Is this a right triangle?
1) x^2+y^2=4^2+5^2
2) y^2+z^2=5^2+(√41)^2
There are 3 variables (x,y,z) in the original condition. Hence, the correct answer is E. Using con 1) and 2), we get the answer as yes when (x,y,z)=(4,5,√41) and the answer as no when (x,y,z)=(3, √32, √34).
_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

Below is 50-51 level question
The product of the units digit, tens digit, and hundreds digit of a positive 3-digit integer n less than 500 is 15, what is the value of n?
1) n>350
2) The sum of the units digit, tens digit, and hundreds digit of a positive 3-digit integer n is 8.
There are 3 variables in the original condition and 1 equation. Hence, there is a high chance that C is the correct answer. Since this is a key question, one of integer questions, we need to apply the CMT 4(A). Hence, using con 1), we get n=351. The condition is sufficient and the correct answer is A.
_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

Is |x-1|>|x+3|?
1) x<-1
2) x<1

If we modifiy the original condition and the question, we should square both sides. Then we get x^2-2x+1>x^2+6x+9? ==> -2x+1>6x+9?, x<-1?. Hence the correct answer is A.
_________________
Senior Manager  Joined: 06 Jun 2016
Posts: 254
Location: India
Concentration: Operations, Strategy
Schools: ISB '18 (D)
GMAT 1: 600 Q49 V23 GMAT 2: 680 Q49 V34 GPA: 3.9
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

could you please solve this question?

There are five homes. If the median price of a home is \$200,000, is the range of all prices greater than \$80,000?
1) The average price of the five homes is \$240,000.
2) Three of five homes have the same price.
Senior Manager  Joined: 06 Jun 2016
Posts: 254
Location: India
Concentration: Operations, Strategy
Schools: ISB '18 (D)
GMAT 1: 600 Q49 V23 GMAT 2: 680 Q49 V34 GPA: 3.9
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

and this one too please

If |r|>|s|, is r>s?
1) r>0
2) s>0
Current Student B
Joined: 24 Jul 2016
Posts: 75
Location: United States (MI)
GMAT 1: 730 Q51 V40 GPA: 3.6
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

Answer is D, both statements are individually enough

Sent from my iPhone using GMAT Club Forum mobile app
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

As always, questions like CMT 3,4 are often on the exam in a more developed form. Take a look at below and you’ll see the type of question that’s really common these days. This one, too, is a 5051-evel problem that is equivalent to CMT 4(A). You must get used to these. You need to know how variable approaches and CMT are related.

(ex 1) (integer) If x and y are postive integers, what is the remainder when 100x+y is divided by 11?
1) x=22
2) y=1
==> If you change the original condition and the prolem, you all ways get the remainder of 1 if you divide 100x by 11 regardless of the value of x. Thus, you only need to know y. Therefore, the answer is . This is a typical 5051 level problem. (CMT 4(A))
_________________
Senior Manager  S
Joined: 24 Jun 2016
Posts: 344
GMAT 1: 770 Q60 V60 GPA: 4
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

1
MathRevolution wrote:

If you change the original condition and the prolem, you all ways get the remainder of 1 if you divide 100x by 11 regardless of the value of x. Thus, you only need to know y. Therefore, the answer is . This is a typical 5051 level problem. (CMT 4(A))

Your answer is wrong. If x = 0, the remainder in the division of 100x by 11 is 0, and if x = 3, the remainder is 3.

Not the first time you've posted a wrong solution in this thread though.

Posted from my mobile device
_________________
Stuck in the 600's and want to score 700+ on the GMAT?
If this describes you, we should talk. I specialize in getting motivated students into the 700's.

\$90/hour as of August 2019. I am not accepting any more students for the Fall 2019 application cycle, but if you are planning to apply in 2020, feel free to reach out!

HanoiGMATTutor@gmail.com
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

2) The question below is a 5051-level problem, and an inequality problem that ignores squared numbers
(ex 2) (inequality) If x and y are positive, is y/x > x/y?
1) y>x
2) y=x+2
==> If you change the original condition and the problem, since x and y are positive numbers, the sign of inequality does not change even if both sides are multiplied by xy. If so, in y/x>x/y?, y2-x2>0?, (y-x)(y+x)>0?, y+x>0, thus, y-x>0?, y>x?. In the case of 1) the answer is yes, and in the case of 2) y-x=2>0 yes, thus the answer is D.

_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

3) Let’s always be careful about the CMT 4(A) like the one below

(ex 3) (statistics) What is the standard deviation of 10 numbers?
1) The standard deviation of them is d, then d2-d=0
2) The product of all the 10 numbers is negative

==> In the original condition, the answer is highly likely to be E with 10 variables. If you go with 1) & 2) you get, from d(d-1)=0, you get d=0,1, and in the case of 2) in order for the mulplication of ten numbers to get negative number, there has to be at least one number that is different from each other. Thus, d≠0, and d=1, hence suffi. Therefore, the answer is C.
_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

If a and b are integers, is ab+1 an odd?
1) a is an even
2) b is an odd
==> In the original condition, C is likely to be the answer since there are 2 variables (a,b). If you solve 1) & 2), you actually get C as an answer. However, this problem, too, is a integer problem(a key question), and if you apply CMT 4(A), if you do 1), a=even, it becomes ab=even ab+1=even+1=odd, hence yes, and suffi. Therefore, the answer is A.
_________________
Senior Manager  S
Joined: 24 Jun 2016
Posts: 344
GMAT 1: 770 Q60 V60 GPA: 4
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

1
MathRevolution wrote:
Below is 50-51 level question
The product of the units digit, tens digit, and hundreds digit of a positive 3-digit integer n less than 500 is 15, what is the value of n?
1) n>350
2) The sum of the units digit, tens digit, and hundreds digit of a positive 3-digit integer n is 8.
There are 3 variables in the original condition and 1 equation. Hence, there is a high chance that C is the correct answer. Since this is a key question, one of integer questions, we need to apply the CMT 4(A). Hence, using con 1), we get n=351. The condition is sufficient and the correct answer is A.

Wait hold on. If the 3 digits are 1, 3, and 5, how is it possible that their sum is 8?

This is a terribly written question.
_________________
Stuck in the 600's and want to score 700+ on the GMAT?
If this describes you, we should talk. I specialize in getting motivated students into the 700's.

\$90/hour as of August 2019. I am not accepting any more students for the Fall 2019 application cycle, but if you are planning to apply in 2020, feel free to reach out!

HanoiGMATTutor@gmail.com
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

CMT 4(B) still often comes out these days.

If a and b are prime numbers, what is the value of a+b?

1) 30≤a<b≤40
2) ab=1,147

==>In the original condition, the answer is highly likely to be C since there are 2 variables (a,b). If you do 1)&2), in the case of 1), you get a=31, b=37, hence unique, and suffi. In the case of 2),too, it becomes 31*37=1,147, therefore suffi. The answer is D. You must not forget about CMT 4(B) like this one with 1) easy and 2) difficult. If you can do A, B easily, consider D. Hence the answer is D.

_________________
Math Revolution GMAT Instructor V
Joined: 16 Aug 2015
Posts: 8017
GMAT 1: 760 Q51 V42 GPA: 3.82
Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

Show Tags

If x≠0, is x^2/|x|<1?
1) -1<x<1
2) 0<x

==>If you change the original condition and the problem, you get is x^2/|x|<1? --> is |x|^2/|x|<1? --> is |x|<1? --> -1<x<1?, so A is the answer.

_________________ Re: The Ultimate Q51 Guide [Expert Level]   [#permalink] 30 Sep 2016, 07:24

Go to page   Previous    1  ...  4   5   6   7   8   9   10   11  ...  44    Next  [ 868 posts ]

Display posts from previous: Sort by

The Ultimate Q51 Guide [Expert Level]

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

Moderator: DisciplinedPrep

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne  