A firm offers terms of 4/12, net 30.

a. What effective annual interest rate does the firm earn when a customer does not take the discount? ____________________ %

b. What is the effective annual rate if the discount is changed to 3% ? ___________________ %

c. What is the effective annual rate if the credit period is increased to 45 days? ___________________ %

d. What is the effective annual rate if the discount period is reduced to 5 days? ___________________ %

Please show all work in long-hand so I can follow along