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Source: Official Guide for GMAT Review 2016 Data Sufficiency ; #20


What is the value of w^(-2)?

What is the value of w^(-2)?

2 Explanations



(1) since w^ (-1) = 2^(-1),
then w^(-2) = w^(-1)(2)
= 2^(-1)(2) = 4^(-1)

(2) i don't know how to interprete this. pls. explain this to me...tx

Nov 5, 2016 • Comment

Sam Kinsman

Hi Amure,

You're right that from statement 1, we can conclude that w^(?2) is 1/4 (or 4^(-1)).

Statement 2 says that w^3 = 8. Since 2^3 = 2*2*2 = 8, we know that w must be equal to 2. So w = 2, and therefore w^(?2) = 2^(-2) = 1/4.

Both statements by themselves are sufficient, and the answer is D

Nov 11, 2016 • Reply


Nicholas Dureault

This question has a mistake in it - be warned.

The prompt is: What is the value of W^(-2)

1) w^(-1) = 1/2
2) w^(8) = 8

for 2, what they meant to say (and is in the answer key) is:
2) 2^(3) = 8

Jan 14, 2016 • Comment

Cydney Seigerman, Magoosh Tutor

Thanks for your message! I've let the content editors know so that this can be corrected. Since we're a small team, it may some time to change that. However, in the meantime, your comment will help other students who visit the forum! Thanks again :)

Jan 15, 2016 • Reply

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Section 6.3 Data Sufficiency

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