In the coordinate plane a slope of the line K is 4 times the y-intercept of the line K. What is the x-intercept of the line K? A. -4 B. 4 C. -1/4 D. 1/4 E. 2 ANS: As Y=4mx+m, from 0=4mx+m we get x=-1/4. Hence, the correct answer choice is C.

If 11!/(11-r)! 11! / (11-r)! = 11*(11-1)*…*(11-r+1) r = 1 : 11 1,000 r = 3 Ans: C

Which of the following inequalities is equal to |x-3|x|| -8 = 0 -8 < x-3x < 8 -8 < -2x < 8 -4 < x < 4 0 <= x < 4 2) x < 0 -8 < x-3|x| < 8 -8 < x+3x < 8 -8 < 4x < 8 -2 < x < 2 -2 < x < 0 Thus, -2 < x < 4 Ans: C

Last visit was: 04 May 2026, 05:36

It is currently 04 May 2026, 05:36

Toolkit

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.

Go to My Error Log Learn more

Request Expert Reply

Confirm Cancel

May 05
Inequalities for GMAT Quant: The Concepts You Must Know
10:00 AM PDT
-
11:00 AM PDT
GMAT Inequalities is a high-frequency topic in GMAT Quant, but many students struggle because the concepts behave differently from standard algebra. Understanding the right rules, patterns, and edge cases can significantly improve both speed and accuracy.
May 06
Paradox & Discrepancy Questions: GMAT Critical Reasoning #3 | GMAT Ninja
08:30 AM PDT
-
09:30 AM PDT
In Episode 3 of our GMAT Ninja Critical Reasoning series, we tackle Discrepancy, Paradox, and Explain an Oddity questions. You know the feeling: the passage gives you two facts that seem completely contradictory....
May 08
$10,000 MBA Scholarships Winners Drawing - Join & Watch the Lucky Winners
08:00 AM PDT
-
08:30 AM PDT
Join the special YouTube live-stream for selecting the winners of GMAT Club MBA Scholarships sponsored by Juno live. Watch who gets these coveted MBA scholarships offered by GMAT Club and Juno.

Back to Forum

Create Topic

Math Revolution Approach (PS)

1 ... 13 14 15 16 17 ... 29

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

20 Aug 2017, 19:13

Kudos

Bookmarks

There are 40 people, 28 invested in A, 16 invested in B, and 18 invested in C. Among 10 of the people who invested in both A and C, 3 also invested in B. All people who invested in B also invested in A. How many people did not invest in any of the three investments?

A. 2 B. 3 C. 4 D. 5 E. 6

Attachment:

8.21.png [ 15.32 KiB | Viewed 1926 times ]

Ans: C

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

20 Aug 2017, 19:15

Kudos

Bookmarks

In a certain conference, if all the n attendees shake hands 105 times, what is the value of n?

A. 10 B. 12 C. 15 D. 16 E. 18

=>
nC2 = 105.
n(n-1)/(1*2) = 105
n(n-1) = 210
n(n-1) = 15*14

Thus n = 15.

Ans: C

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

23 Aug 2017, 01:22

Kudos

Bookmarks

If x-7=√x+√7 , x=?

A. 8+2√7 B. 8-2√7 C. 8+√7 D. 8-√7 E. 7+2√8

=> x-7=√x+√7
(√x+√7 )(√x-√7)=√x+√7
√x-√7=1
√x = 1 +√7
x = (1 +√7)2 = 8 +2√7

Ans: A

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

24 Aug 2017, 01:31

Kudos

Bookmarks

If 11!/(11-r)!<1,000, what is the greatest possible value of r?

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

=> 11! / (11-r)! = 11*(11-1)*…*(11-r+1)

r = 1 : 11 < 1,000
r = 2 : 11*10 = 110 < 1,000
r = 3 : 11*10*9 = 990 < 1,000
r = 4 : 11*10*9*8 = 7290 > 1,000

r = 3

Ans: C

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

25 Aug 2017, 01:14

Kudos

Bookmarks

Which of the following is the closest to 11*10^{20}–9*10^{10}?

A. 10^2 B. 10^7 C. 10^{10} D. 10^{20} E. 10^{21}

=>9*10^{10} is a relatively small number compared with 11*10^{20}.
11*10^{20}–9*10^{10} is approximate to 11*10^{20}, which is similar to 10^{21}.

Ans: E

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

27 Aug 2017, 19:11

Kudos

Bookmarks

Which of the following inequalities is equal to |x-3|x||<8?

A. 0<x<4
B. 0<x<2
C. -2<x<4
D. -2<x<2
E. -2<x<0

=> -8 < x-3|x| <8

1) x >= 0
-8 < x-3x < 8
-8 < -2x < 8
-4 < x < 4
0 <= x < 4

2) x < 0
-8 < x-3|x| < 8
-8 < x+3x < 8
-8 < 4x < 8
-2 < x < 2
-2 < x < 0

Thus, -2 < x < 4

Ans: C

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

30 Aug 2017, 01:27

Kudos

Bookmarks

If 3^x>10, which of the following must be true?

I. x>2
II. x>3
III. x>4

A. I only
B. II only
C. III only
D. I and II only
E. I, II, and III

=> 3^x > 10 > 3^2
Thus x > 2

Ans: A

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

31 Aug 2017, 01:25

Kudos

Bookmarks

If x-7=√x+√7, x=?

A. 8+2√7
B. 8-2√7
C. 8+√7
D. 8-√7
E. 7+2√6

=>x-7=√x+√7
(√x+√7)(√x-√7)=√x+√7
√x-√7 = 1
√x = √7 + 1
x = (√7 + 1)^2
x = 7 + 2√7 + 1 = 8 + 2√7

Ans: A

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

01 Sep 2017, 10:06

Kudos

Bookmarks

(1/11)+(1/12)+……+(1/19)+(1/20) is including in which of the following ranges?

A. 0 ~ (1/5)
B. (1/5) ~ (1/4)
C. (1/4)~(1/3)
D. (1/3)~(1/2)
E. (1/2)~1

=> (1/20) < (1/11), (1/20) < (1/12), …, (1/20) < (1/19).
(1/20) + (1/20) + … + (1/20) < (1/11)+(1/12)+……+(1/19)+(1/20)
(1/20)*10 < (1/11)+(1/12)+……+(1/19)+(1/20)
(1/2) < (1/11)+(1/12)+……+(1/19)+(1/20)

(1/11) < (1/10), (1/12) < (1/10), … , (1/20) < (1/10)
(1/11)+(1/12)+……+(1/19)+(1/20) < (1/10) + (1/10) + … + (1/10) = 1

Thus, 1/2 < (1/11)+(1/12)+……+(1/19)+(1/20) < 1

Ans: E

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

03 Sep 2017, 18:43

Kudos

Bookmarks

If n is the sum of the first 40 positive integers, what is the greatest prime factor of n?

A. 29
B. 31
C. 37
D. 41
E. 43

=> 1 + 2 + … + 40 = (40*41)/2 = 2^3*5*41
Thus the greatest prime factor of n is 41.

Ans: D

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

03 Sep 2017, 18:45

Kudos

Bookmarks

Which of the following is the closest to 11*1010–4*104?

A. 10^2
B. 10^7
C. 10^8
D. 10^9
E. 10^11

=> 4*10^4 is relative small compared with 11*10^10. Thus we can consider 11*10^10 only.
It is close 10^11.

Ans: E

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

06 Sep 2017, 01:34

Kudos

Bookmarks

[GMAT math practice question]

What is the unit digit of 3^5+4^5+5^5+6^5?

A. 5
B. 6
C. 7
D. 8
E. 9

=> 3^1 has a unit digit 3.
3^2 has a unit digit 9.
3^3 has a unit digit 7.
3^4 has a unit digit 1.
3^5 has a unit digit 3.

4^1 has a unit digit 4.
4^2 has a unit digit 6.
4^3 has a unit digit 4.
4^4 has a unit digit 6.
4^5 has a unit digit 4.

5^1 has a unit digit 5.
5^2 has a unit digit 5.
5^n has a unit digit 5 for all positive integers n.

6^1 has a unit digit 6.
6^2 has a unit digit 6.
6^n has a unit digit 6 for positive integers n.

Thus 3 + 4 + 5 + 6 = 18 has the unit digit 8.

Ans: D

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

07 Sep 2017, 01:49

Kudos

Bookmarks

[GMAT math practice question]

If 3^x-3^{x-2}=648, x=?

A. 5
B. 6
C. 7
D. 8
E. 9

=>

3^x-3^{x-2} = 3^{x-2}3^2-3^{x-2} = 3^{x-2}(3^2-1) = 3^{x-2} x 8 = 648
3^{x-2} = 81 = 3^4
x – 2 = 4
x = 6

Ans: B

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

08 Sep 2017, 01:04

Kudos

Bookmarks

[GMAT math practice question]

There are 100 black balls, 100 red balls and 100 green balls evenly mixed in a jar. What is the minimum number of balls to ensure that at least 15 beans selected are the same color?

A. 40
B. 41
C. 42
D. 43
E. 44

=>
We can assume we have 14 black balls, 14 red balls and 14 green balls. After that, if we have just one more ball, it ensures we have 15 balls with a same color.

Thus we need 43 ( = (15-1) + (15-1) + (15-1) + 1 = 14 + 14 + 14 + 1 ) balls.40 balls ensure there are 15 balls that have a same color.

Ans: D

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

10 Sep 2017, 18:24

Kudos

Bookmarks

If the gross profit of a certain company is 20 percent of the revenue from sales of the company, what percent of the cost is the gross profit?

A. 20%
B. 25%
C. 30%
D. 35%
E. 40%

=>
Let R be the revenue of the company. The profit is 0.2*R and the cost is 0.8*R.
The answer is (0.2*R) / (0.8*R) * 100 = 0.25 * 100 = 25(%).

Ans: B

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

[1]

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

[1]

10 Sep 2017, 18:26

Kudos

Bookmarks

[GMAT math practice question]

(7^3)a+(7^2)b+7c+d=1045, where a, b, c, and d are integers from 0 to 6, inclusively, b=?

A. 0
B. 1
C. 2
D. 3
E. 4

=>

1045 = 7*149+2 = 7*(7*21 + 2) +2 = 7*(7*(7*3+0) + 2) + 2
= 7*((7^2)*3 +(7^1)*0 + 2) + 2 = (7^3)*3 +(72)*0 + (7^1)*2 + 2

Thus we have b = 0.

Ans: A

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

[1]

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

[1]

13 Sep 2017, 00:17

Kudos

Bookmarks

[GMAT math practice question]

I. 9/10, 10/11, 11/12, 12/13, 13/14
II. 10/9, 11/10, 12/11, 13/12, 14/13
III. 6/10, 7/10, 8/10, 9/10, 10/10

For which of the following options is the average (arithmetic mean) of the numbers less than the median of numbers?

A. I. only
B. II. only
C. III. only
D. II and III
E. I, II and III

=>

I. Differences between consecutive terms are 10/11 – 9/10 = 1/110, 11/12 – 10/11 = 1/132, 12/13 – 11/12 = 1/156, 13/14 – 12/13 = 1/182. The differences are getting smaller. The average is smaller than the median.

II. Difference between consecutive terms are 11/10 – 10/9 = -1/90, 12/11 – 11/10 = -1/110, 13/12 – 12/11 = -1/132, 14/13 – 13/12 = -1/156. The differences are getting bigger. The average is bigger than the media.

II Difference between consecutive terms are 7/10 – 6/10 = 1/10, 8/10 – 7/10 = 1/10, 9/10 – 8/10 = 1/10, 10/10 – 9/10 = 1/10. All differences are equal. The average is equal to the median.

Ans: A

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

14 Sep 2017, 00:55

Kudos

Bookmarks

[GMAT math practice question]

If x-5=√x+√5 , x=?

A. 6+2√5
B. 6-2√5
C. 6+√5
D. 6-√5
E. 5+2√6

=>
x-5=√x+√5
(√x+√5)(√x-√5)=√x+√5
√x-√5 = 1
√x = 1+√5
x = 1 + 2√5 + 5 = 6 + 2√5

Ans: A

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

15 Sep 2017, 02:03

Kudos

Bookmarks

Which of the following options is closest to (3^{10})(33^{10})?

A. 10^{10}
B. 10^{14}
C. 10^{18}
D. 10^{20}
E. 10^{22}

=>

(3^{10})(33^{10}) = (3^{10})(3*11)^{10} = (3^{10})(3^{10})(11^{10})= (9^{10})(11^{10}) ~ (10^{10})(10^{10}) = 10^{20}

Ans: D

MathRevolution

Math Revolution GMAT Instructor

Joined: 16 Aug 2015

Last visit: 27 Sep 2022

Posts: 10,063

Own Kudos:

20,037

Given Kudos: 4

GMAT 1: 760 Q51 V42 Verified score

GPA: 3.82

Expert

Expert reply

GMAT 1: 760 Q51 V42 Verified score

Posts: 10,063

Kudos: 20,037

17 Sep 2017, 18:45

Kudos

Bookmarks

3 girls and 4 boys line up in a row. If girls stand at the first and boys stand at the last, how many possible cases are there?

A. 96
B. 108
C. 144
D. 192
E. 256

=>

The number of ways that 3 girls permute is 3! = 6 and the number of ways that 4 boys permute is 4! = 24. Those cases happen together and so the number of cases that 3 girls stand at the first and 4 boys stand at the last is 3! * 4! = 6 * 24 = 144.

Ans: C