The equation below shows the formula for calculating the shipping cost, C, for book orders, where p is the weight of the books in pounds. There is a $3 handling fee on every order.
C = $0.75p + $3
Which statement is not true about the cost?
The cost of mailing 10 pounds of books is twice the cost for 5 pounds of books.
The cost for shipping books varies according to the weight of the order.
The cost of the handling fee is unrelated to the wright of the books.
The cost of mailing books increases by $0.75 for each additional pound of books,