Suppose $8000 is invested in a monthly compounded account at 4.2%. Approximately how long will it take for the balance to reach $21,200?

Answer 1

A = P(1 + r/.n)^nt

21,200 = 8000(1 + .042/12)^12t

2.654 = (1 + .0035)^12t

log 2.654 = 12t(log 1.0035)

log 2.654/log 1.0035 = 12t

23.24 years = t