Book for class:Mathematics of investment and credit by Samuel Broverman 7th edition

Make sure to show work

2. Mr Krabs gets a bill for 500 with payment due within 30 days for a shipment of secret Krabby Patty formula supplies. The terms of payment for the bill state that there is a discount of 2% if the bill is paid within 10 days. Mr Krabs doesn't have that amount on hand (in savings, sure... but Pearl is having her birthday party, so he emptied his wallet already). So he decides to take out a short term "loan" from Spongebob and Squidward's salary to take advantage of the discount. What is the largest amount simple interest rate, as an annual rate, that Mr Krabs would be willing to pay on this loan"? (Note: He WILL actually pay interest)