On a purchase of $118, a store offered a payment plan consisting of a $18 down payment and 12 monthly payments of $10 each. What percent of the purchase price, to the nearest tenth of a percent, did the customer pay in interest by using this plan? Choose the correct choice from the following answers
A) 16.7 %  B) 16.2 %  C) 16.5 %  D) 15.5 %  E) 15.3 %

Rationale: "12 * 10 + 18 = 138 ( 18 / 118 ) * 100 = 15.3 answer : e"
Answer: E