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53% (01:17) correct
47% (00:22) wrong based on 150 sessions

\frac{2^{(4-1)^2}}{2^{(3-2)}}=

A. 2^8 B. 2^7 C. 2^6 D. 2^5 E. 2^4

I'm overlooking something incredibly basic here. I know it. It's the first question I got on the GMAT prep math and I was shocked to see I got it WRONG. I've looked over it time and again, but can't find how to get the answer they are saying. They insist it's A, but I can take one look at that and see they are asking 2^6 over 2^2. Which would be 2^4. What am I missing?

Re: I'm missing something basic here, but no idea what [#permalink]
07 Nov 2010, 12:11

2

This post received KUDOS

Expert's post

Pollux wrote:

I'm overlooking something incredibly basic here. I know it. It's the first question I got on the GMAT prep math and I was shocked to see I got it WRONG. I've looked over it time and again, but can't find how to get the answer they are saying. They insist it's A, but I can take one look at that and see they are asking 2^6 over 2^2. Which would be 2^4. What am I missing?

Also please check the questions when posting. Original question is \frac{2^{(4-1)^2}}{2^{(3-2)}}=?

If exponentiation is indicated by stacked symbols, the rule is to work from the top down, thus: a^m^n=a^{(m^n)} and not (a^m)^n, which on the other hand equals to a^{mn}.

Re: I'm missing something basic here, but no idea what [#permalink]
07 Nov 2010, 12:25

Bunuel replied before I posted mine. It all makes sense now. Top down. Top down. Top down. Good to know! _________________

Did I help you? Please give mekudos.

Each moment of time ought to be put to proper use, either in business, in improving the mind, in the innocent and necessary relaxations and entertainments of life, or in the care of the moral and religious part of our nature.

Re: I'm missing something basic here, but no idea what [#permalink]
08 Nov 2010, 15:53

Bunuel wrote:

Pollux wrote:

I'm overlooking something incredibly basic here. I know it. It's the first question I got on the GMAT prep math and I was shocked to see I got it WRONG. I've looked over it time and again, but can't find how to get the answer they are saying. They insist it's A, but I can take one look at that and see they are asking 2^6 over 2^2. Which would be 2^4. What am I missing?

Also please check the questions when posting. Original question is \frac{2^{(4-1)^2}}{2^{(3-2)}}=?

If exponentiation is indicated by stacked symbols, the rule is to work from the top down, thus: a^m^n=a^{(m^n)} and not (a^m)^n, which on the other hand equals to a^{mn}.

I am just curious as I got when the OP posted they said it was \frac{2^{(4-1)^2}}{2^{(3-1)}}=?

and when you answered it you changed the denominator's exponent from (3-1) to (3-2), was it just a typo by the OP? I"m confused because I got 2^7 _________________

"Popular opinion is the greatest lie in the world"-Thomas Carlyle

Remember that 2^{3^2} is not same to (2^3)^2 because the formulas are 2^{x^y} and (2^x)^y = 2^{xy}are different from each other and if we solve 2^{3^2} we get 2^9 (here solve from top to down) and by solving (2^3)^2we get 2^6=64 or 8^2=64

Please! check your Official Answer because the answer can't be 2^8 by solving with the forum timer, I got it wrong as it says that OA is A, which according to rule can't be (just explained above). _________________

"Don't be afraid of the space between your dreams and reality. If you can dream it, you can make it so." Target=780 http://challengemba.blogspot.com Kudos??

Remember that 2^{3^2} is not same to (2^3)^2 because the formulas are 2^{x^y} and (2^x)^y = 2^{xy}are different from each other and if we solve 2^{3^2} we get 2^9 (here solve from top to down) and by solving (2^3)^2we get 2^6=64 or 8^2=64

Please! check your Official Answer because the answer can't be 2^8 by solving with the forum timer, I got it wrong as it says that OA is A, which according to rule can't be (just explained above).

Hi, The question given by original poster was incorrect; it has been edited and corrected. Thanks. _________________

Rules for posting on the verbal forum When you post a question Pls. Provide its source & TAG your questions Avoid posting from unreliable sources such as 1000 series.

Re: 2^(4-1)^2/2^(3-2) [#permalink]
22 Oct 2013, 04:16

Expert's post

waltiebikkiebal wrote:

Small question, could there be an indicator of below 600 level questions? This is obviously a 400-500 level question, and it is a bit misleading for some of us to waste precious time on easy questions, when someone wants to practice questions of a higher level.

Thanks.

Check the tags please:

Attachments

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