The annual interest rate that Joanna paid was 6.5%.
Step-by-step explanation:
Given that Joanna Brandon paid $ 487.50 in interest on a 36 month (3 year) promissory note for $ 2500, to determine what was the rate of interest that Joanna paid, the following calculation must be performed:
487.5 / 3 = 162.5
2500 = 100
162.5 = X
162.5 x 100/2500 = X
16,250 / 2,500 = X
6.5 = X
Thus, the annual interest rate that Joanna paid was 6.5%.
