Please solve for A and B. Thank you

Your firm purchases goods from its supplier on terms of 2.6/15, net 40 . a. What is the effective annual cost to your firm if it chooses not to take the discount and makes its payment on day 40 ? b. What is the effective annual cost to your firm if it chooses not to take the discount and makes its payment on day 50 ? (Hint: Use a 365-day year.) a. What is the effective annual cost to your firm if it chooses not to take the discount and makes its payment on day 40 ? If your firm chooses not to take the discount and makes its payment on day 40 , the effective annual cost is %. (Round to one decimal place.)