Find the interest rate on the loan if he borrowed $2,500 @ an annual interest rate of 6% for 15 years

I think you want the monthly payment.  (Equation is attached).

Monthly Payment equals 21.10

If you are looking for the total interest paid then we need the

Total Loan Cost Formula. (attached)

The monthly loan rate is .06 / 12 = .005 and

number of payments = 12 months * 15 years = 180

Total Cost = .005 * 2,500 * 180 / 1 -(1.005)^-180

= 3,797.36

Total Cost  3,797.36

Minus Principal 2,500

Equals total interest paid = 1,297.36

Step-by-step explanation:

-1 1/3, 3 1/3 = quadrant 2

-3 1/9, -1 1/3= quadrant 3

9, -1 = quadrant 4

1/3, 2 1/3= quadrant 1

1 1/9, -1 1/3= quadrant 4

Step-by-step explanation: