Answer:
10.5%
Step-by-step explanation:
Use the interest formula to fill in the given values and solve for the rate:
I = Prt
where I is the interest earned on principal P at annual rate r for t years.
78.75 = 750·r·1
r =78.75/750 = 0.105 = 10.5%
The rate of interest paid was 10.5%.