Question

Suppose you borrow 13,000 for four years at 7% toward the purchase of a car.

Answer 1

Amount borrowed, P = 13000
Interest, i = 0.07/12 per month
number of periods (months),  n = 4*12 = 48

Monthly payment, 
$A=\frac{P(i*(1+i)^n)}{(1+i)^n-1}$
$=\frac{13000(.07/12*(1+.07/12)^{48}}{(1+.07/12)^{48}-1}$
=311.30   (to the nearest cent)