2^(x+y)/2^(x-y)=?

Question

2^(x+y)/2^(x-y)=?
1) x=1
2) y=2

*An answer will be posted in 2 days

msk0657 · Answer

Given 2^(x+y)/2^(x-y).

We can write it as 2^(x+y)-(x-y)

=> 2^2y

So Stat 2 : clearly this is Sufficient as y = 2.

Option B is correct.

Rushilkhera · Answer

Lets solve the stem first

2(x+y)-(x-y) = 2^2y

Hence Option B satisfies it

ricoh303 · Answer

Solve the stem - you will get 2^2y
Hence B

rikingajjar · Answer

if GMAT will ask such questions then I'll score 800.

Sent from my iPhone using  GMAT Club Forum mobile app

Divyadisha · Answer

2^(x+y)/2^(x-y)= 2^(x+y)- (x-y)= 2^2y

So, it depends on the value of y.

B is the answer

BrentGMATPrepNow · Answer

Target question :    What is the value of 2^(x+y)/2^(x-y)?  
This is a great candidate for  rephrasing the target question .

Let's apply the division law, (x^a)/(x^b) = x^(a-b) 
So, 2^(x+y)/2^(x-y) = 2^ 
= 2^(2y)

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

Statement 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

RELATED VIDEOS
 https://www.youtube.com/watch?v=MyG1K3ee69w

https://www.youtube.com/watch?v=At7a1ibdOTc

MathRevolution · Answer

If we modify the original condition and the question, we get 2^(x+y)/2(x-y)=? --> 2^((x+y)-(x-y))=2^2y. We only have to know y and the correct answer is B.

- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

MathRevolution · Answer

2^x^+^y/2^x^-^y=?

1) x=1
2) y=2

chetan2u · Answer

2^x^+^y/2^x^-^y=\frac{2^x*2^y}{2^x}*2^y=2^{2y}

So we require to know only y..

Statement II gives us value of y..
Sufficient

B

rohit8865 · Answer

2^(x+y-(x-y))----{ as x^m/x^n = X^(m-n)}
=2^(x+y-x+y)
=2^2y=??

(1) x=1 
no info on Y
insuff

(2) y=2
thus 2^2y = 2^4 =16
suff

Ans B

sobby · Answer

2^(x+y-x+y)=2^2y
A-not suff
B-suff , as we know value of Y.

So B.

MathRevolution · Answer

==> If you modify the original condition and the question, from  2^x^+^y/2^x^-^y=2^x^+^y^-^(^x^-^y^)=2^x^+^y^-^x^+^y=2^2^y , you only need to know y. From con 2) y=2, it is sufficient.

Therefore, the answer is B.
Answer: B

HKD1710 · Answer

2^x^+^y/2^x^-^y=?  can be re-written as:

2^x * 2^y / 2^x * 2^{-y}  =?

2^y / 2^{-y}  = ?

2^{2y}  =?

We now only need to know the value of one variable i.e.  y . Hence statement-2 is sufficient. Answer is B.

NandishSS · Answer

Bunuel Can you please merge the above topic. :-)

https://gmatclub.com/forum/2-x-y-2-x-y-221942.html

Bunuel · Answer

_______________
Done. Thank you.

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

2^(x+y)/2^(x-y)=?

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Data Sufficiency (DS) Questions

2^(x+y)/2^(x-y)=?

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards