Final answer:
To calculate the total amount Ken must repay on the $625 loan with 18% simple interest for 1 year, we find the interest is $112.50 and add it to the principal, resulting in a total repayment of $737.50.
Step-by-step explanation:
Yolanda loaned Ken $625 at a simple-interest rate of 18% for 1 year. To calculate the total amount that Ken must repay, we use the formula for simple interest, which is Interest = Principal × rate × time. In this case, the principal is $625, the rate is 18% (or 0.18 when converted to decimal form), and the time is 1 year.
Interest = $625 × 0.18 × 1 = $112.50
To find the total repayment amount, we add the interest to the principal:
Total repayment = Principal + Interest
Total repayment = $625 + $112.50 = $737.50
Therefore, Ken must repay a total of $737.50 at the end of one year.