Rates and Proportions
A rate compares quantities measured in different units, while a proportion states that two ratios are equal. Learn how to calculate unit rates, compare value and solve simple proportion problems in everyday situations.
Learning time: approximately 30 minutes · Beginner to developing level
What You Will Learn
- Understand the difference between a ratio and a rate.
- Calculate a unit rate, such as cost per item or distance per hour.
- Compare two rates fairly.
- Recognise equivalent ratios and proportions.
- Solve simple missing-value proportion problems.
1. What Is a Rate?
A rate compares two quantities measured in different units. Examples include kilometres per hour, dollars per kilogram and pages per minute.
A ratio can compare quantities with the same or different units. A rate is a ratio that compares different units.
2. Find a Unit Rate
A unit rate tells you the amount for one unit. Divide both parts of the rate by the number of units in the second quantity.
Worked example: 30 kilometres in 2 hours
- Write the rate: 30 km in 2 hours.
- Divide both quantities by 2.
- 30 ÷ 2 = 15 km; 2 ÷ 2 = 1 hour.
Unit rate: 15 kilometres per hour (15 km/h).
Another example: Cost per notebook
Four notebooks cost $12. Divide $12 by 4. The unit price is $3 per notebook.
3. Compare Unit Rates
To compare two deals, calculate the unit rate for each deal. Make sure both rates use the same units.
- Pack A: $3 ÷ 6 = $0.50 per pencil.
- Pack B: $4 ÷ 10 = $0.40 per pencil.
Pack B costs less per pencil, so it offers better value if the pencil quality and other conditions are the same.
4. What Is a Proportion?
A proportion is a statement that two ratios are equal. For example, 2:3 and 4:6 are equivalent ratios, so they form a proportion.
Both terms of 2:3 have been multiplied by 2 to make 4:6.
Equivalent ratios are made by multiplying or dividing every term by the same non-zero number.
5. Solve a Missing-Value Proportion
You can use equivalent ratios to find a missing value.
Worked example: 3 : 5 = 12 : x
- Compare the first terms: 3 becomes 12 by multiplying by 4.
- Multiply the second term by the same factor: 5 × 4 = 20.
- Therefore, x = 20.
Answer: 3:5 = 12:20.
Another example: 2 : 7 = x : 21
7 becomes 21 by multiplying by 3. Multiply 2 by 3 as well. Therefore, x = 6.
6. Solve Everyday Problems
Example 1: Travel speed
A car travels 180 kilometres in 3 hours at a steady average rate. What is the distance per hour?
180 ÷ 3 = 60 km/h.
Example 2: Recipe amounts
A recipe uses 2 cups of rice for 5 people. How many cups are needed for 10 people if the same amount per person is used?
10 is twice 5, so double the rice: 2 × 2 = 4 cups.
Example 3: Printing
A printer makes 45 pages in 3 minutes. At the same rate, how many pages does it make in one minute?
45 ÷ 3 = 15 pages per minute.
7. Common Mistakes to Avoid
8. Practice Exercises
Try these before revealing the answers.
- A runner travels 12 km in 3 hours. Find the unit rate in km/h.
- Five pens cost $10. Find the cost per pen.
- Which is cheaper per kilogram: 2 kg for $6 or 3 kg for $7.50?
- Complete the proportion: 2 : 5 = 8 : x.
- Complete the proportion: 4 : 7 = x : 21.
- A machine makes 60 parts in 4 minutes. How many parts does it make per minute?
- A drink mix uses 1 cup of concentrate for 4 cups of water. How much water is needed for 3 cups of concentrate?
Show practice answers and working
- 12 ÷ 3 = 4 km/h.
- $10 ÷ 5 = $2 per pen.
- First: $6 ÷ 2 = $3/kg. Second: $7.50 ÷ 3 = $2.50/kg. The 3 kg pack is cheaper per kilogram.
- 2 becomes 8 by multiplying by 4; x = 5 × 4 = 20.
- 7 becomes 21 by multiplying by 3; x = 4 × 3 = 12.
- 60 ÷ 4 = 15 parts per minute.
- Multiply both parts by 3: 3 cups concentrate need 12 cups water.
9. Test Your Understanding
Choose one answer for each question, then select Check Answers. Each question is worth one point.
10. Free Printable Worksheet
Print this worksheet or save it as a PDF for extra practice.
Learnora — Grades 6–7 Mathematics
Rates and Proportions Worksheet
Name: __________________________ Date: _______________
Instructions: Show your working and include units.
- Eight apples cost $4. Find the cost per apple.
- A cyclist travels 42 km in 3 hours. Find the average distance per hour.
- Complete: 2 : 7 = 6 : ____.
- Complete: 5 : 8 = ____ : 24.
- Compare: 4 kg for $12 or 5 kg for $14. Which costs less per kilogram?
- A recipe uses 3 cups of flour for 6 people. How much flour is needed for 12 people?
Keep practising — you are making progress!
Learnora — Learn Better. Practice Smarter.
Teacher / Parent Answer Key
- $4 ÷ 8 = $0.50 per apple.
- 42 ÷ 3 = 14 km/h.
- 7 becomes 21 by multiplying by 3, so the missing term is 21.
- 8 becomes 24 by multiplying by 3, so the missing term is 15.
- First: $12 ÷ 4 = $3/kg. Second: $14 ÷ 5 = $2.80/kg. The 5 kg option costs less per kilogram.
- Double 3 cups because 12 is twice 6. Answer: 6 cups.
11. Lesson Summary
- A rate compares quantities with different units.
- A unit rate gives the amount for one unit.
- Compare rates using the same units.
- A proportion states that two ratios are equal.
- To solve a missing-value proportion, scale both terms by the same factor.
Educational note: This is a curriculum-neutral lesson for Grades 6–7. Teachers and parents can adapt examples and practice to their local curriculum.