Yumiko invests $2100 in a Treasury Bond at 8.9% interest compounded 4 times per year.
- Find the equation that represents the account balance at time
.
- When will the account double? e.g. when will it be $4200. Round your solution to the nearest tenth of a year.
- Using the compounded interest formula gives
.
- It will take about 7.9 years.