Ichiro took out a subsidized student loan of $13,000 at a 3.6% APR, compounded monthly, to pay for his last two semesters of college. If he will begin paying off the loan in 15 months, how much will he owe when he begins making payments?

Interest accumulates whether he pays or not.
If he does not pay, the principal is not reduced, therefore the accumulated amount in 15 months is equal to
Future value = 13000(1+0.036/12)^15
=$13597.45 (to the nearest cent)