find the compound interest in 8 years and 4 moths if 12500 is invested at 15% compounded monthly

Question

compound amount and compound interest

Answer 1

8 years and 4 months is 100 months. 15% annually is 15/12=1.25% monthly. The monthly compound interest factor is (1+0.0125), which gives the amount plus interest after one month. After 100 months the factor is (1.0125)^100=3.4634 approx. Multiplying by 12,500 gives the amount after 100 months: 43,292.55, so interest=30,792.55.