hey all i cant seem to figure out what im doing wrong for this question (business math)

Question

the question is: A loan payment of ​$1500.00 was due 30 days ago and another payment of

​$900.00 is due 80 days from now. What single payment 90 days from now will pay off the two obligations if interest is to be 9​% and the agreed focal date is 90 days from​ now?

i did it like 1500 (1+.09*30/365)+900(1+.09*80/365) = 2428.85

i used the formula s=p(1+rt) since the due date is BEFORE the focal date right?

however when i submitted my answer, the thing told me the answer is 2446.60

im so confused! any help here? did i mess up my formula or my calculations?

thanks :))

Answer 1

The $1500 was due 30 days ago and payment will be made in 90 days. So the money has been borrowed for 120 days.

So the payment on that amount:

1500(1 + .09(120/365))

The $900 is due in 80 days, but you are going to pay it off in 90 days. That means you will have borrowed that amount for only 10 days.

Payment due:

900(1 + .09(10/365))

Calculate those numbers, add them together and likely you will get the answer 2446.60.