1. **Stating the problem:** You buy a TV for 800 and agree to pay in 18 equal monthly payments with an interest rate of 1.5% per month on the unpaid balance. We need to find the monthly payment amount and the total interest paid. 2. **Understanding the problem:** This is an example of an installment loan with equal monthly payments and a monthly interest rate of 1.5%. The loan amount (principal) is $800$, number of payments $n=18$, and monthly interest rate $i=0.015$ (1.5%). 3. **Formula for monthly payment:** The monthly payment for an installment loan is given by $$ P = \frac{r \times PV}{1 - (1+r)^{-n}} $$ where $P$ = monthly payment, $r = 0.015$ = monthly interest rate, $PV = 800$ = present value (loan amount), $n = 18$ payments. 4. **Calculating monthly payment:** $$ P = \frac{0.015 \times 800}{1 - (1+0.015)^{-18}} = \frac{12}{1 - (1.015)^{-18}} $$ Calculate the denominator: $$ (1.015)^{-18} = \frac{1}{(1.015)^{18}} \approx \frac{1}{1.30477} = 0.7663 $$ Thus, $$ 1 - 0.7663 = 0.2337 $$ Therefore, $$ P = \frac{12}{0.2337} \approx 51.35 $$ 5. **Total amount paid:** Total amount paid over 18 months: $$ 51.35 \times 18 = 924.3 $$ 6. **Total interest paid:** Interest paid is total amount paid minus principal: $$ 924.3 - 800 = 124.3 $$ **Final answers:** - Each monthly payment is approximately $\boxed{51.35}$. - Total interest paid is approximately $\boxed{124.3}$.