If Ann saves x dollars each week and Beth saves y dollars each week, what is the total amount that they save per week?

[AAPL]

Official Guide

If Ann saves x dollars each week and Beth saves y dollars each week, what is the total amount that they save per week?

1) Beth saves $5 more per week than Ann saves per week
2) It takes Ann 6 weeks to save the same amount that Beth saves in 5 weeks

OA C

[Brent@GMATPrepNow]

Official Guide

If Ann saves x dollars each week and Beth saves y dollars each week, what is the total amount that they save per week?

1) Beth saves $5 more per week than Ann saves per week
2) It takes Ann 6 weeks to save the same amount that Beth saves in 5 weeks

OA C

Given: Ann saves x dollars each week and Beth saves y dollars each week

Statement 1: Beth saves $5 more per week than Ann saves per week
We can write: y = x + 5
Since this equation does not provide it sufficient information to find the value of x + y, statement 1 is NOT SUFFICIENT

Statement 2: It takes Ann 6 weeks to save the same amount that Beth saves in 5 weeks.
We can write: 6x = 5y
Since this equation does not provide it sufficient information to find the value of x + y, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
When we combine the two statements we get to the following system of equations:
y = x + 5
6x = 5y
Since we have two different linear equations with two variables, we COULD solve the system for x and y, which means we COULD answer the target question with certainty (although we would never waste precious time on test day actually calculating the value of x + y)

Since we COULD answer the target question with certainty, the combined statements are SUFFICIENT

Answer: C

Cheers,
Brent