Myerson borrowed $8,500 at 9% ordinary interest for 200 days. After 120 days, he made a partial payment of $4,000. What is the final amount due on the loan?

Interest due at the end of 120 days

= 8500 (120/365) (.09) = 251.51

so of his $4000 payment, $3748.49 will go towards reducing the debt.

so balance owing = 8500 - 3748.49

= 4751.51

interest for the remaining 80 days

= 4751.51 (.09) (80/365) = 93.73

total owing at the end = 4751.51+93.73

= $4845.23