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.
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.
