Solve the problem.
The Paperback Trader is a book store that takes in used paperbacks for 20% of their cover price and sells them for 50% of their cover price. Pat brings in a stack of 16 paperback books to trade and gets $17.50 credit. Some of the books had a cover price of $7.97, the rest $3.97. She wants to get some Tom Clancy books having a cover price of $7.97. How many $7.97 books did she bring in and how many Clancy books can she get without paying any additional cash?
◦ 10 $7.97 books, 2 Clancy books
◦ 6 $7.97 books, 2 Clancy books
◦ 6 $7.97 books, 5 Clancy books
◦ 6 $7.97 books, 4 Clancy books