In 2002, the bookstore sold 1000 paperback books and 1500 hardback books. in 2003, the store sold 15% more paperback books and 5% more hardback books than sold in 2002. by what percent did the total number of books sold by the store increase from 2002 to 2003? . a. 20% / b. 60%. /c. 9% / d.15%