Jacob invested $300 in a savings account and earned $81 in interest at the end of 9 years.

What was the interest rate?

A.

3%

B.

3.5%

C.

4%

D.

4.5%

r = (1/t) (A/P - 1)

r = (1/9) ((300/81) - 1)

Reduce the expression by cancelling the common factors.

r = (1/9) (100/27 - 1)

Combine 100/27 and - 1 using a common denominator.

r = (1/9) (100-1⋅27 / 27)

Simplify the numerator.

r = (1/9) (73/27)

r = 0.30041152

converting r decimal to a percentage

R = 0.30041152 * 100 = 30.0412%/year

A. 3%