Source: Official Guide for GMAT Review 2016 Data Sufficiency ; #11


What is the cube root of w?

What is the cube root of w?

3 Explanations


Trinity Sheppard

I have a follow up question. If either of the statements were even rooted would the statement then be insufficient since then w could be negative or positive?

Dec 13, 2017 • Comment

Sam Kinsman, Magoosh Tutor

That's a great question. Keep in mind that when the root symbol appears on the test, they actually want the principal square root (i.e. the positive root only). This idea explained here: (the blog post is about the GRE, but it applies to the GMAT as well).

So if Statement 1 were an even root, it would be referring to a positive root, and it would still be sufficient.

Dec 21, 2017 • Reply


Jordan Knoll

Just a note that in the explanation for the first statement Mike says "square root" but the question asks for "cube root". Clearly just a slip of the tongue, because he does write cube root on the screen. :)

Oct 29, 2016 • Comment

Cydney Seigerman, Magoosh Tutor

Thanks for letting us know about this, Jordan! I've let our content team know so that when this video is updated, the mistake can be corrected. That said, with the variety of projects going on right now, that may take some time. In the meantime, your comment will definitely help clarify possible confusion. Thanks again :D

Oct 30, 2016 • Reply


Gravatar Mike McGarry, Magoosh Tutor

Aug 17, 2015 • Comment

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Official GMAT Material

Official Guide for GMAT Review 2016

Official Guide for the GMAT 2015 14th Ed.

Official Guide for the GMAT 13th Ed.

Official Guide for the GMAT 12th Ed.

Revised GRE PDF 2nd Ed.

Section 6.3 Data Sufficiency

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