Here is an interesting GMAT number property problem solving question. Concept tested : number of factors.

Integer x has n factors; 3x has 3 factors; Which of the following values can n take?

I. 1

II. 2

III. 3

A. I only

B. II only

C. I or II

D. II or III

E. I or III

Miguel Costa says

2 factors right?

They must be 1 and 3.

Thanks

Miguel Costa says

Hi,

Could you please help me out on this exercise?

My thinking below:

If 3x has exactly 3 factor (we dont know if they are distinct factors) it has necessarily 1;x;3;3x has factors, which implies that x=3.

Considering this, 3 has 2 factors : 1 and 3, itself.

So the answer must be 2 factors. right?