Answer :
cost of books = $500
selling price = $ 1200
Profit = $1200 - $500 = $700
profit from each book = $7
Number of books = total profit/ profit per book = $700/$7 = 100
So there were 100 books.
selling price = $ 1200
Profit = $1200 - $500 = $700
profit from each book = $7
Number of books = total profit/ profit per book = $700/$7 = 100
So there were 100 books.