How long will it take for the balance of an account to double if the savings account earns 0.75% annual interest compounded monthly?

Hint: Set up the problem using the formula: A=P (1+r/n) ^nt.

Let the amount deposited (principal) be x, then the amount after the required time = 2x.

A = P (1 + r/n) ^nt: where A is the future value = 2x, P is the principal = x, r is the rate = 0.75%, n is the number of accumulation in a year = 12, t is the number of years.

2x = x (1 + 0.0075/12) ^12t

2 = (1 + 0.000625) ^12t

log 2 = 12t log (1.000625)

log 2 / log (1.000625) = 12t

1109.38 = 12t

t = 92 years