Unit rates and unit ratios

A unit rate is a ratio that has a denominator of 1. A unit rate is also called a unit ratio. (They mean the same thing.)

$\frac{5}{4}$ and $3:8$ and $40\mbox{ to }10$ are ratios, but they are not unit ratios.

$\frac{1.25}{1}$ and $0.375:1$ and $4\mbox{ to }1$ are unit ratios.

Any ratio can be converted into a unit ratio by dividing the numerator and the denominator by the denominator.



Example 1

At a school dance, there are 6 girls for every 3 boys.


What is the ratio of girls to boy as a unit rate? (girls per boy)

What is the ratio of boys to girl as a unit rate? (boys per girl)


Example 2

20 sticks of gum costs $1.25


What is the price per stick of gum?


What is the ratio of sticks to price as a unit ratio?





Q1: Write the following ratio as a unit rate (km per hr): 474 km in 6 hours [show answer]

Q2: Write the unit rate (cost per muffin). $2.00 for 5 muffins [show answer]

Q3: A 16-oz jar of peanut butter costs $4.39. To the nearest cent, find the unit price in cents per ounce. [show answer]