Finding Unit Rates: Graded Practice Set (Grade 8)

Grade 8 focus

This practice set is for the specific skill finding a unit rate: rewriting a rate so that one quantity is 1, then stating the result with correct units.

Use this record with, not instead of, the linked overview and broader practice materials:

• For concept and introductory explanation, see Finding Unit Rates — Grade 8 Unit Overview.
• For wider comparison and application work, see Unit Rates and Rate Interpretation: Graded Practice Set (Grade 8).
• For multi-step real-world uses, see Applying Unit Rates to Solve Problems — Grade 8 Unit Overview.

How to use this set

For each question:

1. Identify the two quantities and their units.
2. Decide which quantity should become 1.
3. Divide both parts of the rate by the same number.
4. Write the answer in per 1 form, such as 3 dollars per notebook or 72 kilometres per hour.

Common mistakes to watch for

• Dividing the wrong way around. Repair: ask, "What should be 1 in my final answer?"
• Forgetting units. Repair: always write per language.
• Stopping after simplifying a ratio that is not yet a unit rate. Repair: check whether one quantity is actually 1.
• Rounding too early. Repair: keep the exact decimal until the end, then round only if asked.

Graded practice problems

Set A: direct whole-number division

1. [Easy] A pack of 3 notebooks costs $12. Find the cost per notebook.
2. [Easy] A car travels 180 km in 3 hours. Find the speed in km/h.
3. [Easy] A recipe uses 10 cups of flour for 5 batches. Find the flour per batch.
4. [Easy] A worker earns $84 for 7 hours of work. Find the pay per hour.
5. [Easy] A printer makes 96 flyers in 8 minutes. Find the number of flyers per minute.
6. [Easy] A bag holds 18 apples and costs $9. Find the cost per apple.

Set B: direct division with decimals or non-integer unit rates

7. [Easy-Medium] A bottle holds 1.5 L of juice and costs $3. Find the cost per litre.
8. [Easy-Medium] A runner travels 7.5 km in 0.5 hour. Find the speed in km/h.
9. [Medium] A package of 8 markers costs $5.60. Find the cost per marker.
10. [Medium] A machine produces 250 parts in 4 hours. Find the number of parts per hour.
11. [Medium] A taxi travels 13.2 km using 1.1 L of fuel. Find the distance per litre.
12. [Medium] A bag of rice costs $11.25 for 2.5 kg. Find the cost per kilogram.

Set C: choose the correct unit rate

13. [Medium] A hiker walks 14 km in 4 hours. Find the speed in km/h.
14. [Medium] 9 movie tickets cost $117. Find the cost per ticket.
15. [Medium] 2.4 m of ribbon costs $7.20. Find the cost per metre.
16. [Medium] A faucet fills 18 L in 6 minutes. Find the flow rate in litres per minute.
17. [Medium] A cyclist rides 45 km in 1.5 hours. Find the speed in km/h.
18. [Medium] A box of 15 granola bars has mass 0.9 kg. Find the mass per bar in kilograms.

Set D: harder interpretation and careful unit work

19. [Hard] A bus travels 312 km in 4.8 hours. Find the average speed in km/h.
20. [Hard] A phone plan costs $27.50 for 5 GB of data. Find the cost per GB.
21. [Hard] A gardener uses 7.2 L of water over 12 plants. Find the water used per plant in litres.
22. [Hard] A baker pays $18.90 for 3.5 kg of strawberries. Find the cost per kilogram.
23. [Hard] A conveyor belt moves 528 boxes in 7.5 hours. Find the number of boxes moved per hour.
24. [Hard] A train travels 187.5 km in 2.5 hours. Find the speed in km/h.

Answer key

1. $4 per notebook
2. 60 km/h
3. 2 cups per batch
4. $12 per hour
5. 12 flyers per minute
6. $0.50 per apple
7. $2 per litre
8. 15 km/h
9. $0.70 per marker
10. 62.5 parts per hour
11. 12 km/L
12. $4.50 per kg
13. 3.5 km/h
14. $13 per ticket
15. $3 per metre
16. 3 L/min
17. 30 km/h
18. 0.06 kg per bar
19. 65 km/h
20. $5.50 per GB
21. 0.6 L per plant
22. $5.40 per kg
23. 70.4 boxes per hour
24. 75 km/h

Full solutions for the hardest third

17. A cyclist rides 45 km in 1.5 hours. Find the speed in km/h.

We want a rate per 1 hour.

45 km in 1.5 h

Divide both quantities by 1.5:

45 / 1.5 = 30 1.5 / 1.5 = 1

So the unit rate is:

30 km/h

18. A box of 15 granola bars has mass 0.9 kg. Find the mass per bar in kilograms.

We want the mass per 1 bar.

0.9 kg for 15 bars

Divide both quantities by 15:

0.9 / 15 = 0.06 15 / 15 = 1

So the unit rate is:

0.06 kg per bar

Check: 15 x 0.06 = 0.9, so the answer is consistent.

19. A bus travels 312 km in 4.8 hours. Find the average speed in km/h.

We want the distance per 1 hour.

312 km in 4.8 h

Divide:

312 / 4.8 = 65

So:

312 km / 4.8 h = 65 km / 1 h

The average speed is:

65 km/h

20. A phone plan costs $27.50 for 5 GB of data. Find the cost per GB.

We want the cost per 1 GB.

$27.50 for 5 GB

Divide by 5:

27.50 / 5 = 5.50 5 / 5 = 1

So the unit rate is:

$5.50 per GB

21. A gardener uses 7.2 L of water over 12 plants. Find the water used per plant in litres.

We want the amount of water per 1 plant.

7.2 L for 12 plants

Divide by 12:

7.2 / 12 = 0.6 12 / 12 = 1

So the unit rate is:

0.6 L per plant

22. A baker pays $18.90 for 3.5 kg of strawberries. Find the cost per kilogram.

We want the cost per 1 kg.

$18.90 for 3.5 kg

Divide by 3.5:

18.90 / 3.5 = 5.4

So:

$18.90 / 3.5 kg = $5.40 / 1 kg

The unit rate is:

$5.40 per kg

23. A conveyor belt moves 528 boxes in 7.5 hours. Find the number of boxes moved per hour.

We want the number of boxes per 1 hour.

528 boxes in 7.5 h

Divide:

528 / 7.5 = 70.4

So the unit rate is:

70.4 boxes per hour

24. A train travels 187.5 km in 2.5 hours. Find the speed in km/h.

We want the distance per 1 hour.

187.5 km in 2.5 h

Divide by 2.5:

187.5 / 2.5 = 75

So the unit rate is:

75 km/h

Self-check prompts

After each answer, ask yourself:

• Did I make the correct quantity equal to 1?
• Did I divide both quantities by the same number?
• Did I include units?
• Does my answer make sense in context?

Extension

When these feel secure, move to comparison and decision problems in the broader unit-rates practice set and then to multi-step applications.