Answer:
The size of the repayment check is $21,868.50.
Explanation:
The repayment check is going to be:
R = Principal + Interest
The principal is $19,221. We have to find the value of the interest.
The interest can be calculated as simple interest, given by the following formula:

In which P is the principal, r is the annual interest rate, in decimal, and t is the time, in years.
In this problem, we have that:
,

The time is 17 months. However, we must convert this value to years. Each year has 12 months. So 17 months is
years. So

The interest value is:



The size of the repayment check is:
R = Principal + Interest



The size of the repayment check is $21,868.50.