Directly Proportional and Inversely Proportional
Learn how direct proportion doubles together and inverse proportion halves when one doubles. Let’s get started! 🚀
Video Lesson
Watch and learn the basics
Flashcards
Review key concepts visually
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🛎️ What Is Direct Proportionality?
- In direct proportion, doubling one value will double the other.
- If 1 watermelon costs £4, then 2 cost £8 and 4 cost £16.
🛎️ What Is Inverse Proportionality?
- In inverse proportion, doubling one value will halve the other.
- For a task, 15 people take 2 hours, but 30 people only take 1 hour.
🛎️ Spotting the Difference Quickly
- In direct proportion, the unit rate stays the same.
- In inverse proportion, the product of the two quantities stays the same.
Practice Questions
Test your understanding
At a supermarket, 3 watermelons cost in total. How much would 7 watermelons cost if each watermelon costs the same?
Correct! 🎉 +10 pointsNot quite right
The cost of one watermelon is . For 7 watermelons, the total cost is .
A factory task takes 5 workers 6 hours to complete. How many hours will it take if 10 workers are available?
Correct! 🎉 +10 pointsNot quite right
The task requires a constant 30 work hours. With 10 workers, the time required is hours.
A construction job requires 8 workers and 15 days to complete. How many days would it take if only 5 workers are available?
Correct! 🎉 +20 pointsNot quite right
The task requires a constant work days. With 5 workers, the time required is days.
A train covers 360 km in 6 hours. How much time will it take to cover 450 km at the same speed?
Correct! 🎉 +20 pointsNot quite right
The speed of the train is km/h. To cover 450 km, the time required is hours.
A car consumes 12 litres of fuel to travel 240 km. How far can the car travel with 18 litres of fuel?
Correct! 🎉 +20 pointsNot quite right
The car’s fuel efficiency is km/litre. With 18 litres of fuel, the car can travel km.
A project requires 16 workers to complete in 12 days. How many more workers would be required to complete the project in 8 days?
Correct! 🎉 +30 pointsNot quite right
The task requires a constant worker-days. To complete it in 8 days, the total number of workers needed is . Subtracting the 16 workers already there, .
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Interactive Activity
Adjust the constant k to see how direct and inverse proportion affect a data table
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