Last visit was: 23 Apr 2026, 11:29 It is currently 23 Apr 2026, 11:29
Close
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
Your Progress

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.
Close
Request Expert Reply
Confirm Cancel
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
|a-b|=?

1) |a+b|=10
2) |a^2-b^2|=20

==> In the original condition, there are 2 variables (a,b) and in order to match the number of variables to the number of equations, there must be 2 equations. Since there is 1 for con 1) and 1 for con 2), C is most likely to be the answer. By solving con 1) and con 2), you get |a^2-b^2|=|a+b||a-b|=20, 10|a-b|=20, |a-b|=2.

The answer is C.
Answer: C
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is a<b?

1) a<0
2) |b|<1

==> In the original condition, there are 2 variables (a, b) and in order to match the number of variables to the number of equations, there must be 2 equations. Since there is 1 for con 1) and 1 for con 2), C is most likely to be the answer. By solving con 1) and con 2), from -1<b<1, if a=-0.1 and b=-0.2, no, but if b=0.1 and a=-0.1, yes.

Hence, the answer is E.
Answer: E
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If x and y are integers, what are the values of x and y?

1) 2^x3^y=16/27
2) x+y=1

==> For con 1), you get 2^x3^y=16/27=2^43^-3, then x=4 and y=-3. Therefore, the answer is A. In other words, it is CMT 4(A), in which A and C are both the answers. In the original condition, there are 2 variables, so the answer is C, but since it is an integer question, you apply CMT 4(A) and get the final answer as A.

This is a 4950 level question.
Answer: A
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If x, y, z are positive integers, is xyz divisible by 6?

1) x, y, z are consecutive.
2) x+y+z is a multiple of 3.

==> The product of 3 consecutive integers is always a multiple of 6. For con 1), it is yes and sufficient, and for con 2), (x,y,z)=(1,2,3) yes but (x,y,z)=(2,2,2) no, hence it is not sufficient.

Therefore, the answer is A.
Answer: A
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
3^-(x+y)/3^-(x-y)=?

1) x=3
2) y=2
==> If you modify the original condition and the question, you get 3^-(x+y)/3^-(x-y)=3^x-y+x-y=3^-2y, so you only need to know y.

The answer is B.
Answer: B
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is |x+y|<|x|+|y|?

1) x+y<0
2) x<y

==> If you modify the original condition and the question, for |x+y|<|x|+|y|?, you can square both sides, and if you expand from (|x+y|)^2<(|x|+|y|)^2? Or, (x+y)^2<(|x|+|y|)^2?, you get x^2+y^2+2xy<|x|^2+|y|^2+2|xy|?, or x^2+y^2+2xy<x^2+y^2+2|xy|?, 2xy<2|xy|?, xy<|xy|?. However, in con 1) and con 2), xy<0 is not mentioned, so the answer is E.

Answer: E
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If x and y are positive integers and y(2^x)=24, x=?

1) x 2
2) y is even

==> In the original condition, there are 2 variables (a,b), and in order to match the number of variables to the number of equations there must be 2 equations as well. Since there is 1 for con 1) and 1 for con 2) C is most likely to be the answer.
By solving con 1) and con 2), you get 24=6(2^2).

The answer is C.
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
When x+y is integer, is y an integer?

1) x is an integer.
2) x+2y is an integer.

==> In the original condition, there are 2 variables (x,y) and 1 equation (x+y=integer). In order to match the number of variables to the number of equations, there must be 1 more equation. Since there is 1 for con 1) and 1 for con 2), D is most likely to be the answer. For con 1), from x=integer and x+y=integer, integer+y=integer, you get y=integer, which is yes and sufficient. For con 2), from x+2y=x+y+y=integer, integer+y=integer, you get y=integer, which is also yes and sufficient.

Therefore, the answer is D.
Answer: D
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
For x and y, what is the value of x?

1) (x-3)(x+y)=0
2) (x-3)(2x+y)=0

==> In the original condition, there are 2 variables (x,y) and in order to match the number of variables to the number of equations, there must be 2 equations. Since there is 1 for con 1) and 1 for con 2), C is most likely to be the answer. By solving con 1) and con 2), you get x=3, which is unique and sufficient.

Therefore, the answer is C.
Answer: C
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If mr≠0, m/r=?

1) (m+r)/r=3
2) r/(m+r)=1/3

==> In the original condition, there are 2 variables (m,r) and in order to match the number of variables to the number of equations, there must be 2 equations. Since there is 1 for con 1) and 1 for con 2), C is most likely to be the answer. By solving con 1) and con 2), you get con 1) = con 2), so from m/r+1=3, you get m/r=2, hence it is unique and sufficient.

Therefore, the answer is D.
Answer: D
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
1-c-d=?

1) c+d=-1
2) c=-1-d

==> In the original condition, there are 2 variables (c,d) and in order to match the number of variables to the number of equations, there must be 2 equations. Since there is 1 for con 1) and 1 for con 2), C is most likely to be the answer. By solving con 1) and con 2), you get con 1) = con 2), so both of them becomes c+d=-1, and 1-c-d=1-(c+d)=1-(-1)=2, hence it is unique and sufficient.

Therefore, the answer is D.
Answer: D
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is x^3y^2z<0?

1) x^2y<0
2) yz<0


==> If you modify the original condition and the question, when xyz≠0, you get xz<0?. There are 3 variables (x,y,z), and in order to match the number of variables to the number of equations, there must be 2 equations. Since there is 1 for con 1) and 1 for con 2), E is most likely to be the answer. By solving con 1) and con 2), you get x^2y<0, y<0 and yz<0, z>0. Since x is unknown, it is not sufficient.

Therefore, the answer is E.
Answer: E
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is a positive integer x an even number?

1) The smallest prime factor of x is 2.
2) The greatest prime factor of x is 13.

==> In the original condition, there is 1 variable (x) and in order to match the number of variables to the number of equations, there must be 1 equations. Since there is 1 for con 1) and 1 for con 2), D is most likely to be the answer. For con 1), since x always has 2 as the factor, you get x=even, hence yes, it is sufficient. For con 2), you get x=2*13 yes but x=13 no, hence it is not sufficient.

The answer is A.
Answer: A
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If x, y, and z are positive integers, is x+y divisible by 3?

1) x+z is divisible by 3
2) y+z is divisible by 3

==> In the original condition, there are 3 variables (x,y,z) and in order to match the number of variables to the number of equations, there must be 3 equations. Since there is 1 for con 1) and 1 for con 2), you need 1 more equation, so E is most likely to be the answer. By solving con 1) and con 2), if x=y=z=3 yes, but if z=2, x=y=1 no, hence it is not sufficient.

Therefore, the answer is E.
Answer: E
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is the standard deviation of set A greater than that of set B?

1) The median of set A is greater than that of set B
2) The average (arithmetic mean) of set A is greater than that of set B

==> In the original condition, more than 90% of the questions related to the the relationship between median, mean, and standard deviation have E as the answer.

The answer of this question is also E.
Answer: E
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is n>0?

1) n>-1
2) |1+n| > |n-3|

==> In the original condition, there is 1 variable (n), and in order to match the number of variables to the number of equations, there must be 1 equation. Since there is 1 for con 1) and 1 for con 2), D is most likely to be the answer. Also, for inequality questions, if the range of the question includes the range of the condition, the condition is sufficient. Thus, for con 1), the range of the question does not include range of the condition, hence it is not sufficient. For con 2), if you square both sides, you get |1+n|^2 > |n-3|^2, (1+n)^2 > (n-3)^2, n^2+2n+1>n^2-6n+9, 8n>8, n>1, so the range of the question includes the range of the condition, hence it is sufficient.

Therefore, the answer is B.
Answer: B
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Out of 50 people, there are 35 people with college degrees and 30 females. How many females with college degree are there?

1) 10 are males with college degree.
2) 5 are females without college degree.

==> If you modify the original condition and the question, it is a 2 by 2 question that appears most frequently on gmat math.

Attachment:
7.19.png
7.19.png [ 2.96 KiB | Viewed 1523 times ]

According to the table above, there are 4 variables (w,x,y,z) and 3 equations (w+x+y+z=50, w+y=35, w+x=30). In order to match the number of variables to the number of equations, there must be 1 more equation. Since there is 1 for con 1) and 1 for con 2), D is most likely to be the answer. You get con 1) = con 2), and then you get w=25.

The answer is D.
Answer: D
   1  ...  11   12   13   14   15  ...  29