Final answer:
The question involves solving a linear equation representing a loan repayment schedule to determine the monthly payment and the total amount paid. The equation indicates that Harry pays back $200 per month over 45 months, resulting in a total of $9000 paid back to the bank.
Step-by-step explanation:
The equation D = -200t + 9000 represents the remaining amount of a loan after t months when Harry makes fixed monthly payments. To determine the monthly payment Harry took for his loan from the bank, we can analyze the structure of this linear equation. The coefficient of t (-200) tells us that Harry pays $200 each month. If we set D to zero and solve for t, the solution would give us the total number of months needed for Harry to pay off the loan completely.
To calculate the total amount paid over the life of the loan, we multiply the monthly payment by the number of months it takes to pay the loan in full. Given that the initial loan amount is $9000, as per the equation when t = 0, and each payment reduces this amount by $200, it would take 45 months ($9000 divided by $200 per month) to fully repay the loan. Hence, the total amount paid back would be $200 * 45 = $9000.