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MathidiaMathematics Academy
Proportion and rates
Lesson 54 of 75
Challenge

Speed and other rates

Objective. Use rate as one quantity measured per unit of another.

  1. 1. Learn
  2. 2. Worked example
  3. 3. Practice
  4. 4. Feedback
  5. 5. Continue

Learn: the key idea

Speed and other rates is built on a small number of dependable facts. Scale quantities and compare rates in realistic situations. Represent the information first, choose a method deliberately, show each step and use an inverse operation or estimate to check that the result fits the question.

Worked example

A car travels 350 km in 7 hours. Find its average speed.

350 … 7
Illustrated card showing 350 … 7
  1. 1Identify the mathematical information and what must be found.
  2. 2Represent it with a number line, diagram, table or expression where helpful.
  3. 3Apply the relevant fact carefully and keep each line clear.
  4. 4Check the result against the conditions in the question: 50 km/h.

Answer: 50 km/h

Concept mastery

Based on your past attempts at this lesson — the question types to practise again come first.

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Practice

Practice happens on its own screen, one question at a time. Answers stay hidden until you submit yours, and you can stop and pick up at the same question later.

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Common mistake. A common mistake in speed and other rates is to apply a remembered procedure before reading the signs, units or order carefully. Write the structure first, then calculate and check.

Your progress

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