I think it's February and March.

Feb. 13th+15days=Feb 28th
If the 13th is Friday, then if we add 15 days, the 28th is a Saturday.
Now, we need to add 13 days in March, which will be Friday again.

lilu wrote:I think it's February and March.

Feb. 13th+15days=Feb 28th
If the 13th is Friday, then if we add 15 days, the 28th is a Saturday.
Now, we need to add 13 days in March, which will be Friday again.

Yupe. That's the right answer! Thanks.

kanha81 wrote:If a year which is not a leap year has two consecutive months with a friday as thirteenth, what are the months?

Really not sure why this question is on a GMAT forum, but the general rule is that in non-leap years, the dates/days in March are an exact match for the dates/days in February (at least the first 28 days of March). This is true because February has 28 days and 28 is divisible by 4, so there are no "extra" days to push the weeks offline in March.