Question

A moving Company weighs 20 boxes you have packed that contain either books or clothes and says the total weight is 404 pounds. You know that a box of books weighs 40 pounds and a box of clothes weighs 7 pounds. Find how many boxes of books and how many boxes of clothes you packed.

Answer 1

number of boxes of books ---> x
number of boxes of clothing ---> 20-x

solve
40x + 7(20-x) = 404