In this activity, we will learn how to use direct proportion to work out problems.
Example 1
A car uses petrol at the rate of 1 gallon for every 30 miles travelled (30 mpg)
How many gallons will it take to travel 177 miles?
Answer
1 gallon = 30 miles
30 miles = 1 gallon
1 mile = 1/30 gallon
177 miles = 1/30 × 177 = 177 ÷ 30 = 5.9 gallons
Example 2
How many miles can it travel on 5.9 gallons?
Answer
1 gallon = 30 miles
5.9 gallons = 30 × 5.9 = 177 miles
Does that make sense? Let's try some questions together now.