A firm offers terms of 1/10, net 40. a. What effective annual interest rate does the firm earn when a customer does not take the discount? Effective annual interest rate % b. What effective annual interest rate does the firm earn if the discount is changed to 2 percent? Effective annual interest rate % c. What effective annual interest rate does the firm earn if the credit period is increased to 60 days? Effective annual interest rate % d. What effective annual interest rate does the firm earn if the discount period is increased to 15 days? Effective annual interest rate %