Question

coral invested $500 in an account that earns simple interest at the rate of %5.5 each year. Assuming coral does not invest anymore money it will take how many years for coral to have %720 in her account?

Answer 1

The number of years it will take coral to have $720 in her account is 8 years

Explanation:

The principal amount coral invested, P = $500

The simple interest rate earned per year, r = 5.5%

The amount in coral account after t years, A = $720

The formula for simple interest is given as follows;

`Simple \ Interest, \ SI = (Principal, P * Rate, r * Time, t)/(100)`

The formula for amount, A = SI + P

Therefore, we have;

`A = (P * r * t)/(100) + P`

`720 = (500 * 5.5 * t)/(100) + 500`

`720 - 500 = (500 * 5.5 * t)/(100)`

`220 = (500 * 5.5 * t)/(100)`

22000 = 500 × 5.5 × t

t = 22000/(500 × 5.5) = 8

The number of years, t, it will take coral to have $720 in her account = 8 years.