Data Sufficiency

Max@Math Revolution wrote:2^(x+y)/2^(x-y) = ?

1) x=1
2) y=2

Target question: What is the value of 2^(x+y)/2^(x-y)?

This is a great candidate for rephrasing the target question.
Aside: Here's our video with tips on rephrasing the target question: https://www.gmatprepnow.com/module/gmat- ... cy?id=1100

We can apply the division law, (x^a)/(x^b) = x^(a-b) here.
So, 2^(x+y)/2^(x-y) = 2^[(x+y) - (x-y)]
= 2^(2y)

We can now REPHRASE the target question...
REPHRASED target question: What is the value of 2^(2y)?

Statement 1: 1) x = 1
This information has no bearing on the REPHRASED target question
So, statement 1 is NOT SUFFICIENT

Statement 2: y = 2
PERFECT.
This means that 2^(2y) = 2^4 = 16
Since we can answer the REPHRASED target question with certainty, statement 2 is SUFFICIENT

Answer = B

Cheers,
Brent

Here's a similar question to practice with: https://www.beatthegmat.com/practice-exa ... 90958.html

Cheers,
Brent