You borrowed $25 from your friend. You paid him back in full after 6 months. He charged $2 for inter

You borrowed $25 from your friend. You paid him back in full after 6 months. He charged $2 for interest. What was the annual simple interest rate that he charged you? Use the formula: I = Prt.

We have I = 2, P = 25, t = 0.5

2 = 25(r)0.5

Divide each side by 0.5
4 = 25r

Divide each side by 25
r = 4/25
r = 0.16
As a percentage, this is 16%