A bookseller sells his books at a 20% markup in price. If he sells a book for $24.00, how much did he pay for it? Choose the correct choice from the following answers
A) $ 14.40  B) $ 14.00  C) $ 10.00  D) $ 9.60  E) $ 20.00

Rationale: let the cost price of book = x selling price of book = 24 $ markup % = 20 ( 120 / 100 ) x = 24 = > x = 20 answer e
Answer: E