Grade 9 · Math · Unit 5 of 15
Rates & Percents
Unit rates, discounts and proportions
What your child practises
Unit rates and best buys, percent of an amount, percent increase and decrease, proportions in ratios, and negative rates such as a diver going down.
Ontario Curriculum expectation: B3.3, B3.5 · rates, percentages and proportions, and the effect of negative signs
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
A cyclist rides 168 km in 4 hours at a steady pace. What is the rate in km per hour?
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42
Hint: Divide the distance by the time: 168 ÷ 4 = 42.
Question 2
A jacket costs $180. It is 50% off. What is the sale price in dollars?
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90
Hint: Pay 50% of the price: 180 × 50 ÷ 100 = 90.
Question 3
A diver's depth changes at a rate of −4 m per minute (a negative rate means going down). What is the total change in depth after 3 minutes?
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-12 m
Hint: Multiply the rate by the time: (−4) × 3 = −12.
Question 4
The ratio of cats to dogs at a shelter is 4:6. There are 18 dogs. How many cats are there?
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12
Hint: 18 ÷ 6 = 3 groups, so the cats number 3 × 4 = 12.
Question 5
What is 60% of 80?
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48
Hint: 60% means 60/100. Multiply: 60 × 80 ÷ 100 = 48.
Question 6
A price rises from $40 to $52. By what percent did it increase?
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30 %
Hint: Change ÷ original × 100 = 12 ÷ 40 × 100 = 30%.