Source: Official Guide for the GMAT 13th Ed. Data Sufficiency; #15 Official Guide for the GMAT 2015 14th Ed. Data Sufficiency; #15

1

What is the cube root of w?

What is the cube root of w?

2 Explanations

1

frank v ghiselli

if the square root was given in place of the fifth root, would it be insufficient because it is even, therefore allowing one of the values to be negative?

Aug 17, 2017 • Comment

Sam Kinsman, Magoosh Tutor

Hi Frank,

If S1 gave us the square root of w instead of the 5th root, S1 would still be sufficient.

Let's say that S1 said:

(sqrt w) = 4

That would mean that w = 16, because the square root of 16 is 4. We wouldn't have a negative answer. The square root of -16 doesn't exist, since we cannot take the square root of a negative number. Therefore, w cannot be -16. In this case.

So if we are given the square root of w, we will still only have one possible value for w, and the statement is sufficient.

Aug 26, 2017 • Reply

1

Gravatar Mike McGarry, Magoosh Tutor

Dec 30, 2013 • Comment

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Section 6.3 Data Sufficiency

Section 6.3 Data Sufficiency

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