Concept

A rate is a ratio that is used to compare different kinds of quantities. 
A unit rate describes how many units of the first type of quantity corresponds to one unit of the second type of quantity.

Rule

1. Write the ratio of the two quantities as a fraction.

   Quantity 1 per Quantity 2 means Quantity 1Quantity 2

2. Calculate unit rate by dividing the numerator by the denominator.

3. Use the unit rate to write and solve the proportion.

Example

The table shows how many miles a truck driver travels over a time. How many miles will he have driven after 8 hours?

Solution

Write the ratio of any data point as a fraction.

DistanceHours = 120 miles2 hours

Calculate unit rate by dividing the numerator by the denominator.

DistanceHours = 60 miles per hour

Use the unit rate to write and solve a proportion

60 miles1 hour = x miles8 hours

60 × 81 × 8 = 4808

Answer: 480 miles

Pre-requisite Skills

Equivalent Fractions (5.10.5)

Ratios and Fractions (6.6.2)

Multiply Fractions (6.7.7)