Question

How can unit rates be helpful at the supermarket?

Answer 1

Unit rates allow us to easily compare the price of two or more similar products for equivalent amounts.

Explanation:

Example:

Suppose you want to choose between two boxes of corn flakes.
`color(white)("XXX")`One box weighs 18 oz. and costs $4.29;
`color(white)("XXX")`the other weights 22 oz. and costs $5.19.

Unless you have a calculator handy or really enjoy standing in the supermarket aisle doing mental arithmetic, it is difficult to decide which is the better deal.

However if the unit prices are posted so that
`color(white)("XXX")`the 18 oz. box indicates that it costs 23.8 cents/oz, and
`color(white)("XXX")`the 22 oz. box indicates that it costs 24.7 cents/oz.
we can easily see that the 18 oz. box is the better choice.