A trader deposits ₦50,000 in a savings account at an annual interest rate of 12%. If the interest is calculated on a simple interest basis, how much will the trader have in the account at the end of 18 months?

Using the simple interest formula: $I = P \times r \times t$, where P = ₦50,000, r = 12% per annum = 0.12, and t = 18 months = 1.5 years. Therefore, $I = 50,000 \times 0.12 \times 1.5 = ₦9,000$. Total amount = ₦50,000 + ₦9,000 = ₦59,000. Common errors include using t = 18 instead of 1.5, giving ₦158,000, or computing 12% of ₦50,000 only once.