Source: Official Guide for the GMAT 13th Ed. Data Sufficiency; #1 Official Guide for the GMAT 2015 14th Ed. Data Sufficiency; #1

16

What is the value of |x|?

What is the value of |x|?

2 Explanations

3

Kyle Frederiksen

So in this problem, if the question simply asked what is the value of X would neither of the answers been sufficient since x in option 2 has 2 values?

Nov 5, 2015 • Comment

Cydney Seigerman, Magoosh Tutor

If the question asked for the value of x, neither statement alone would be sufficient to answer the question. However, using the information from both statements, we could determine the value of x. Statement 2 tells us that x = +/-2. From there, we can use the information in Statement 1 to determine that x must be negative. Therefore, x = -2, and the answer would be (C), both Statements 1 and 2 together are sufficient to answer the question but neither statement is sufficient alone.

Nov 11, 2015 • Reply

9

Gravatar Mike McGarry, Magoosh Tutor

Dec 28, 2013 • Comment

Mitra Arabandi

for the question types 'what is the value' if a statement prompt proves that, that the data is completely insufficient than statement a in the answer choice should be true, shouldn't it ?? There were other DS questions when an answer prompt was absolutely not sufficient to answer the question prompt but we chose 'a' because it was completely insufficient. What is the difference here ?

Sep 13, 2015 • Reply

Cydney Seigerman, Magoosh Tutor

Hi Mitra,
For all DS questions, (A) is selected when Statement 1 alone is sufficient, while Statement 2 alone is not sufficient to answer the question. In a similar manner, (B) is selected when Statement 1 alone is not sufficient but Statement 2 alone is sufficient to answer the question, which is the case in this problem. Most likely in the other problem you're referring to, it was the case that Statement 1 was sufficient while Statement 2 was insufficient.

Nov 4, 2015 • Reply

Vivek Sivadas

Hi Mitra,
I feel that you are referring to questions in which statement 1 gives an answer " NO" rather than insufficient. As long as you get a Yes or No ans in a DS question, it is sufficient. If you get a maybe or either, its insufficient.

Nov 14, 2016 • Reply

SONIKA VASANTH

In statement #1 x =|x|, wkt if x=-3 then the result will be negative -|-3| =-3 ( -3 is considered as +3)
but if -|3| again we have a positive 3 so the result will be -3. shouldn't statement 1 be sufficient?

Dec 3, 2016 • Reply

Sam Kinsman, Magoosh Tutor

Hi Sonika,

You're right that statement 1 (S1) is true, then x can be -3. However, notice that if S1 is true, x can be ANY negative number.

For example, x could be -5. We would have:

x = -|x|
-5 = -|-5|
-5 = -5

So if S1 is true, x can be any negative number. Therefore, S1 is not sufficient: we don't have enough information to find the value of |x|.

Dec 7, 2016 • Reply

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Section 6.3 Data Sufficiency

Section 6.3 Data Sufficiency

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