Peter is at a lumber yard. He gets 2 free boxes of nails for every 10 boards he buys. Write an expression for the number of boxe
s of nails Peter will get if he buys n boards. If each box has 100 nails, explain how to write an expression to find how many nails Peter will have if he purchases 90 boards.
The algebraic expression n/10, where n is the number of boards, represents the number of times he gets 2 free boxes of nails. So 2(n/10), or n/5, is the number of boxes, and 100(n/5), or 20n, is the number of nails. Substituting 90 in for n, Peter will get 1,800 nails.
