Question

If $800 is deposited into an account that pays 6%/a compounded monthly, how many months will it take the investment to grow to $2000?
a)48
b)184
c)188
d)333

Answer 1

You need
800(1 + 0.06/12)^n = 2000
now solve for n. It will take a little over 15 years.

Answer 2

2000 = 800 [1 + (.06 / 12)]^m

log(2000 / 800) = m log(1.005)

m = log(2.5) / log(1.005)