GMATinsight wrote:

Is n/14 an Integer?

1) 3n/14 is an Integer

2) 2n/14 is an Integer

Source:

http://www.GMATinsight.comEDIT: corrected explanation.

Questions dealing with number properties can almost always be solved logically, with very little calculation.

We'll look for such an answer, a Logical approach.

(1) If we were told that n were an integer, than this would be sufficient, as 3 and 14 are mutually prime. Since it is not, we can manipulate things however we like. For example, choosing 3n/14 = 1, would give n/14 = 1/3, which is not an integer while choosing 3n/14 = 3 would give n/14 = 1, which is

Insufficient.

(2) this implies that n/7 is an integer which in turn implies that n is an integer divisible by 7. If n has 2 in its prime factors, then n/14 is an integer and if it does not, it is not.

Insufficient.

Combined.

From (2) we learn that n is an integer. Therefore, based on the observation that 3 and 14 are mutually prime, (1) implies that n/14 must be an integer.

Sufficient.

(C) is our answer

_________________

Sign up for 7-day free trial

I am a CR Expert - Ask Me ANYTHING about CR

I am a DS Expert - Ask Me ANYTHING about DS

The best DEAL of the year has finally arrived! Save up to $320 on your GMAT course.

Expires on Nov 24th.