Credit terms. Find the effective annual rate of the following credit terms:

a. 2.4% discount if paid within 14 days or net within 30 days

b. 1.8% discount if paid within 31 days or net within 60 days

c. 0.6% discount if paid within 17 days or net within 45 days

d. 0.7% discount if paid within 20 days or net within 30 days