Case of Negetive Factors of a Number

[mohit.wrangler]

Question:

A
Number of distinct factor of 47

B
The number of distinct prime factor of 48

My take on the problem:

A: # of distinct factors {-1,1,-47,47} is 4
B: # of prime factors {3,2} is 2

Hence, the answer should be A.
However, the official answer given is C, considering only positive factors of 47.

What is the correct answer if the same question appears in GRE?
(Note:ETS official guide, mentions that negative factors are valid. So, don't forget to address this if you want to argue that answer is C )

[tommywallach]

On the GRE, only positive factors are EVER considered.

-t

[mohit.wrangler]

Below is one of the bullet points in ETS GRE Official Guide under the title Mathematical Conventions for the Quantitative Reasoning Measure of the GRE revised General Test. page #133



After reading this, from an Official Guide, I don't see any reason to consider the "factors" by default as "positive factors".

[tommywallach]

ETS are just wrong there, about their own test (hilarious, right?). Negative factors have never been considered on any GRE question I've ever seen (or GMAT, for that matter). You're right it's in the book, but it's one of the many times they've just been totally silly. Believe me, there are lots of them. Their most recent book was so full of mistakes they more or less had to recall it.

-t