You invest $5000 at 3% compounded monthly for 15 years. How much interest will you earn?

Answer 1

P = Po * (1+r)^n

r = (3%/12)/100% = 0.0025 = Monthly %
rate expressed as a decimal.

n = 12Comp./yr * 15 yrs. = 180 Compounding periods.

Solve for P.

I = P-Po