Scientists often use rates to express quantities and to make changes from one unit to another.
The ability to find the unit price for a particular object you wish to purchase is often a valuable tool for comparing prices. Unit price is the cost of one of a particular item. You can compare unit prices to help determine which item is a better buy. In this case, the 36-ounce box is a better buy. It is important that students learn to estimate the answers to rate and ratio problems.