Cascade International Currently Has Credit Terms of Net 45 with No

Cascade International currently has credit terms of net 45 with no discount and an average collection period of 48 days. Cascade believes that if it offered a 2/15 discount, 60% of its sales
Would be collected within the discount period and the remaining customers would pay in 50 days.
By how many days will Cascade's average collection period change if the discount policy is
Adopted?

A) -29 days
B) -28 days
C) -19 days
D) -10 days
E) 2 days