Suppose $9,500 is compounded annually for 22 years. If no other deposits are made, what rate is needed for the balance to quadruple in that time?

Question

Interest Rate _________%

Answer 1

38000 = 9500(1 + r/1)¹⁽²²⁾

4 = (1 + r)²²

²²√4 = 1 + r

1.065 = 1 + r

r = 0.065 = 6.5%