Please help I cant figure out how to solve this problem.

Your company just purchased $18,000 of product form a vendor. The vendor offers payment terins of 4/15, net 60 . How much will you need to pay if you make payment within 15 days? How much will you need to pay the vendor if you make payment between 16 and 60 days? What is the cost (\%) of failing to take the cash discount