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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## Four friends, Charles, Mike, Brian, and John, went on a... tagged by: swerve ##### This topic has 3 expert replies and 0 member replies ### Top Member ## Four friends, Charles, Mike, Brian, and John, went on a... Four friends, Charles, Mike, Brian, and John, went on a shopping trip. If Mike spent$400 more than Brian did, John spent $1200 less than Charles did, and Charles spent$400 more than Mike did, how many more dollars did Brian spend than John did?

A. $400 B.$600
C. $800 D.$1000
E. $1200 The OA is A. If Mike spent$400 more than Brian, this can be written like M = B + 400 (1).

If John spent $1200 less than Charles, this can be written like J = C - 1200 (2). If Charles spent$400 more than Mike, this can be written like C = M + 400 (3).

Then, I need to find how many more dollars did Brian spent than John, Can I write this like B - J = $? From (1), B = M - 400 Then (1) - (2), B - J = M - 400 - C + 1200 = M - C + 800 (4). Then, (3) into (4), B -J = M - M - 400 + 800, finally, B - J = 400. Right? Please, can any expert explain this PS question for me? I would like to know how to solve it in less than 2 minutes. I need your help. Thanks. ### GMAT/MBA Expert GMAT Instructor Joined 04 Oct 2017 Posted: 551 messages Followed by: 11 members Upvotes: 180 Quote: Four friends, Charles, Mike, Brian, and John, went on a shopping trip. If Mike spent$400 more than Brian did, John spent $1200 less than Charles did, and Charles spent$400 more than Mike did, how many more dollars did Brian spend than John did?

A. $400 B.$600
C. $800 D.$1000
E. $1200 The OA is A. If Mike spent$400 more than Brian, this can be written like M = B + 400 (1).

If John spent $1200 less than Charles, this can be written like J = C - 1200 (2). If Charles spent$400 more than Mike, this can be written like C = M + 400 (3).

Then, I need to find how many more dollars did Brian spent than John, Can I write this like B - J = $? From (1), B = M - 400 Then (1) - (2), B - J = M - 400 - C + 1200 = M - C + 800 (4). Then, (3) into (4), B -J = M - M - 400 + 800, finally, B - J = 400. Right? Please, can any expert explain this PS question for me? I would like to know how to solve it in less than 2 minutes. I need your help. Thanks. Hi swerve, Let's take a look at your question. The approach you used is absolutely correct. But we can solve it Just by adding up all three equations. $$M=B+400\ ...\left(i\right)$$ $$J=C-1200\ ...\left(ii\right)$$ $$C=M+400...\left(iii\right)$$ Adding Eq(i), (ii) and (iii), we get: $$M+J+C=B+400+C-1200+M+400$$ $$M+J+C=B+C+M-400$$ $$J=B-400$$ $$B-J=400$$ Therefore, Option A is correct. Hope it helps. I am available if you'd like any follow up. _________________ GMAT Prep From The Economist We offer 70+ point score improvement money back guarantee. Our average student improves 98 points. Free 7-Day Test Prep with Economist GMAT Tutor - Receive free access to the top-rated GMAT prep course including a 1-on-1 strategy session, 2 full-length tests, and 5 ask-a-tutor messages. Get started now. ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15380 messages Followed by: 1872 members Upvotes: 13060 GMAT Score: 790 swerve wrote: Four friends, Charles, Mike, Brian, and John, went on a shopping trip. If Mike spent$400 more than Brian did, John spent $1200 less than Charles did, and Charles spent$400 more than Mike did, how many more dollars did Brian spend than John did?

A. $400 B.$600
C. $800 D.$1000
E. $1200 Mike spent$400 more than Brian did.
Let B=1000, implying that M = 1000+400 = 1400.

Charles spent $400 more than Mike did. Since M=1400, C = 1400+400 = 1800. John spent$1200 less than Charles did.
Since C=1800, J = 1800-1200 = 600.

How many more dollars did Brian spend than John did?
B-J = 1000-600 = 400.

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### GMAT/MBA Expert

GMAT Instructor
Joined
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Posted:
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swerve wrote:
Four friends, Charles, Mike, Brian, and John, went on a shopping trip. If Mike spent $400 more than Brian did, John spent$1200 less than Charles did, and Charles spent $400 more than Mike did, how many more dollars did Brian spend than John did? A.$400
B. $600 C.$800
D. $1000 E.$1200

We can create the equations:

M = B + 400

and

J = C - 1200

and

C = M + 400

Adding equations 2 and 3, we have:

J + C = C + M - 800

J = M - 800

Adding M = B + 400 and J = M - 800, we have:

M + J = B + M - 400

J = B - 400

J + 400 = B

We see that Brian spent $400 more than John. Answer: A _________________ Scott Woodbury-Stewart Founder and CEO scott@targettestprep.com See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews • FREE GMAT Exam Know how you'd score today for$0

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