Question

You put $500 in a savings account. The account earns $15.75 simple interest in 6 months. What is the annual interest rate?

Answer 1

6.3%

Explanation:

We're gonna use the simple interest formula: A = P(1 + rt)

A = Final amount (500 + 15.75 = 515.75)

P = Starting amount (500)

r = rate (?)

t = number of years (.5 since it's been half a year)

515.75 = 500(1 + 0.5r)

Disitribute the 500 to the equation inside the parenthesis

515.75 = 500 + 250r

Subtract 500 from both sides

515.75 = 500 + 250r

- 500 - 500

15.75 = 250r

Divide both sides by 250

15.75/250 = 250r/250

r = 0.063