GMATPrepNow wrote:

MathRevolution wrote:

How many factors of 330 are odd numbers greater than 1?

A. 3

B. 4

C. 5

D. 6

E. 7

*An answer will be posted in 2 days.

330 is a pretty small #, so it wouldn't take long to LIST all of the odd factors.

We'll use the fact that 330 = (2)(3)(5)(11) AND the fact that ODD x ODD = ODD

So, the ODD factors of 330 are:

- 3

- 5

- 11

- (3)(5)

[we need not evaluate this since we'll just going to count the factors in our list]- (3)(11)

- (5)(11)

- (3)(5)(11)

Done!

Answer:

Nice! I did it this way too and I think it's very solid and intuitive. Yours is slicker though, I got the first 6 and then realized 330/2=165 for the last one. Your hint about not needing to follow through on the multiplication, and just listing the factors, is a huge time-saver for that.