4000.00 bond with a yearly interest rate of 4% the total interest was $800.00 what was the length of the investment

Answer 1

4000(1.04)^n = 4800
1.04^n = 1.2
take log of both sides and use log rules

n log1.04 = log 1.2
n = log 1.2/log 1.04 = appr 4.65 years