Question

Jess deposited $5,000 into an account that earns simple interest. After 9 years, Jess had earned $3,150 in interest. What was the interest rate of the account?

Answer 1

The interest rate of Jess's account was 7%

Explanation:

A = P * (1 + rt)

A = final amount

P = initial principal balance

r = annual interest rate

t = time (in years)

Replacing with the values we know:

A = P * (1 + rt)

8,150 = 5,000 * (1 + r * 9)

8,150/5,000 = 1 + 9r

1.63 = 1 + 9r

1.63 - 1 = 9r

0.63 = 9r

r = 063/9

r = 0.07 = 7%

The interest rate of Jess's account was 7%

Answer 2

The interest rate of Jess's account was 7%

Explanation:

____________________________________

A = P × (1 + rt)

A = final amount

P = initial principal balance

r = annual interest rate

t = time (in years)

___________________________________

A=8,150

P=5,000

8,150 = 5,000 × (1 + r × 9)

8,150÷5,000 = 1 + 9r

1.63 = 1 + 9r

1.63 - 1 = 9r

0.63 = 9r

r = 063÷9

r = 0.07 = 7%