Question

You deposit $400 in an account. The account earns $18 simple interest in 9 months.What is the annual interest rate?​

Answer 1

Use the formula,

I = Prt

P = Principal amount = 400

I = interest = 18

r = annual rate

t = time in years = 9/12 = 3/4

so,

18 = 400*r*3/4

r = 0.06

so the annual interest rate is 0.06 or 6%