Jennifer has 60 dollars more than Brian. If she were to

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Jennifer has 60 dollars more than Brian. If she were to give Brian 1/5 of her money, Brian would have 25% less than the amount that Jennifer would then have. How much money does Jennifer have?

A. 40
B. 100
C. 120
D. 140
E. 180

The OA is the option B.

This answer confused me. What is the equation that I should use here? Experts, can you show me how should you solve this PS question? Thanks.

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by GMATGuruNY » Sun Feb 11, 2018 3:48 am
M7MBA wrote:Jennifer has 60 dollars more than Brian. If she were to give Brian 1/5 of her money, Brian would have 25% less than the amount that Jennifer would then have. How much money does Jennifer have?

A. 40
B. 100
C. 120
D. 140
E. 180
We can PLUG IN THE ANSWERS, which represent Jennifer's amount.
When the correct answer is plugged in, Brian's new amount will be 75% of Jennifer's new amount, with the result that his new amount will be 25% LESS than her new amount.
Since the problem involves PERCENTS, start with J=100.

B: J=100
Since Jennifer has 60 more dollars than Brian, B=40.
After Jennifer gives Brian 1/5 of her $100 -- in other words, after Jennifer gives Brian $20 -- we get:
New J = 100-20 = 80.
New B = 40+20 = 60.
(new B)/(new J) = 60/80 = 3/4 = 75%.
Success!

The correct answer is B.
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by Brent@GMATPrepNow » Sun Feb 11, 2018 7:45 am
M7MBA wrote:Jennifer has 60 dollars more than Brian. If she were to give Brian 1/5 of her money, Brian would have 25% less than the amount that Jennifer would then have. How much money does Jennifer have?

A. 40
B. 100
C. 120
D. 140
E. 180

The OA is the option B.

This answer confused me. What is the equation that I should use here? Experts, can you show me how should you solve this PS question? Thanks.
Here's one approach:

Let J = Jennifer's $
Let B = Brian's $

Jennifer has 60 dollars more than Brian.
So, J = B + 60

If Jennifer were to give Brian 1/5 of her money, Brian would have 25% less than the amount that Jennifer would then have.
If Jennifer were to give Brian 1/5 of her money, then Jennifer has (4/5)J dollars, and Brian has B + (1/5)J dollars

If Brian has 25% less than the amount that Jennifer has, then Brian's amount = 3/4 Jennifer's amount.
So, we can write: 3/4(4/5)J = B + (1/5)J
Simplify, to get (3/5)J = B + (1/5)J
Multiply both sides by 5 to get: 3J = 5B + J
Rearrange: 2J = 5B

We now have the system:
J = B + 60
2J = 5B

When we solve it, we get J = 100 (as well as B = 40)

Answer: B

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by Scott@TargetTestPrep » Tue Feb 13, 2018 5:39 pm
M7MBA wrote:Jennifer has 60 dollars more than Brian. If she were to give Brian 1/5 of her money, Brian would have 25% less than the amount that Jennifer would then have. How much money does Jennifer have?

A. 40
B. 100
C. 120
D. 140
E. 180

We can let the amount of money Jennifer has = J and the amount of money that Brian has = B and create the equation:

J = B + 60

B = J - 60

If Jennifer gives 1/5 of her money to Brian, she would have:

(4/5)J

and Brian would have:

B + (1/5)J = J - 60 + (1/5)J

Since Brian would now have 25% less money than Jennifer, we have:

J - 60 + (1/5)J = (3/4)[(4/5)J]

J - 60 + (1/5)J = (3/5)J

Multiplying the equation by 5, we have:

5J - 300 + J = 3J

3J = 300

J = 100

Answer: B

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