Suppose you write a book. A printer charges $4 per book to print it and you spend$3500 on advertising. You sell the book for $15 a copy. How many copies must you sell so that your income from sales is greater than your total cost? 1 Answer Mar 13, 2018 Answer: You need to sell at least $319$books. Explanation: You earn $11 per book because

$15-$4=$11 Your other cost is advertising. You must sell at least ($3500)/("$11/book") or $318.2$books to offset that cost. Therefore, you must sell at least $319\$ books.