1. **State the problem:** We need to find the total payment required to pay off a loan of 1500 at an interest rate of 6% after 18 months. 2. **Formula used:** For simple interest, the total payment is calculated by: $$\text{Total Payment} = P + I$$ where $P$ is the principal and $I$ is the interest. The interest $I$ is given by: $$I = P \times r \times t$$ where $r$ is the annual interest rate (in decimal) and $t$ is the time in years. 3. **Convert time to years:** Since 18 months = $\frac{18}{12} = 1.5$ years. 4. **Calculate interest:** $$I = 1500 \times 0.06 \times 1.5 = 1500 \times 0.09 = 135$$ 5. **Calculate total payment:** $$\text{Total Payment} = 1500 + 135 = 1635$$ **Final answer:** The total payment required to pay off the loan after 18 months is $1635$.