Answer:
155
Step-by-step explanation:
Let p represent the number of paperback books sold. Then p-60 is the number of hardback books sold. Total revenue will be the sum of products of price and quantity.
2.99p +3.49(p-60) = 795 . . . . . an equation for total revenue
6.48p -209.40 = 795.00 . . . . . simplify
6.48p = 1004.40 . . . . . . . . . . . . add 209.40
1004.40/6.48 = p = 155 . . . . . . divide by the coefficient of p
The owner sold 155 paperback books.