1. At the school bookstore, Harrison purchases 3 notebooks for $2.50 each, 10 pens for $0.35 each, and 5 mechanical pencils for $0.89 each. By what amount (a) is the cost of the mechanical pencils greater than the cost of the pens?

At the school bookstore, Harrison purchases 3 notebooks for 2.50 each, 10 pens for 0.35 each, and 5 mechanical pencils for 0.89 each. By what amount (a) is the class=