1. **State the problem:** Calculate the interest earned on a principal of 40000 from March 15, 2022 to August 10, 2022 at an interest rate of 5.25% per annum. 2. **Formula for simple interest:** $$I = P \times r \times t$$ where $I$ is interest, $P$ is principal, $r$ is annual interest rate (in decimal), and $t$ is time in years. 3. **Convert interest rate to decimal:** $$r = \frac{5.25}{100} = 0.0525$$ 4. **Calculate time using Approximate Time (360-day year):** Count days from March 15 to August 10: March 15 to March 31 = 16 days April = 30 days May = 30 days (approximate) June = 30 days July = 30 days August 1 to 10 = 10 days Total days = 16 + 30 + 30 + 30 + 30 + 10 = 146 days Convert to years: $$t = \frac{146}{360}$$ 5. **Calculate interest (Approximate Time):** $$I = 40000 \times 0.0525 \times \frac{146}{360}$$ $$I = 40000 \times 0.0525 \times 0.4055$$ $$I = 40000 \times 0.02128 = 851.20$$ 6. **Calculate time using Actual Time (365-day year):** Count days exactly: March 15 to March 31 = 17 days April = 30 days May = 31 days June = 30 days July = 31 days August 1 to 10 = 10 days Total days = 17 + 30 + 31 + 30 + 31 + 10 = 149 days Convert to years: $$t = \frac{149}{365}$$ 7. **Calculate interest (Actual Time):** $$I = 40000 \times 0.0525 \times \frac{149}{365}$$ $$I = 40000 \times 0.0525 \times 0.4082$$ $$I = 40000 \times 0.02143 = 857.20$$ **Final answers:** - Interest (Approximate Time) = 851.20 - Interest (Actual Time) = 857.20