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Class 8 Maths — Direct and inverse proportion

Tell direct proportion from inverse proportion, and use each to find a missing quantity.

Name: ________________________

  1. 1.y is in inverse proportion to x. When x is 4, y is 15. What is y when x is 10?

  2. 2.A car travels 180 km in 3 hours at a steady speed. How far does it go in 5 hours, in km? Give just the number.

  3. 3.If 4 kg of rice costs ₹200, what do 7 kg cost? Give just the number.

  4. 4.Two quantities are in inverse proportion. Which of these stays the same as they change?

    • a) Their product
    • b) Their sum
    • c) Their difference
    • d) Their ratio

  5. 5.If 5 pens cost ₹60, what do 8 pens cost? Give just the number.

  6. 6.12 pipes fill a tank in 20 minutes. How many minutes would 15 pipes take?

  7. 7.6 workers take 12 days to finish a job. Match each number of workers to the days they would take at the same rate.

    • 4 workers
    • 8 workers
    • 9 workers
    • 12 workers
    • 18 workers
    • 6 days
    • 18 days
    • 9 days
    • 8 days
    • 4 days

  8. 8.A journey takes 4 hours at 60 km per hour. How many hours would it take at 80 km per hour?

Answer key — Class 8 Maths — Direct and inverse proportion

  1. 1. 6
  2. 2. 300
  3. 3. 350
  4. 4. a) Their product
  5. 5. 96
  6. 6. 16
  7. 7. 4 workers → 18 days; 8 workers → 9 days; 9 workers → 8 days; 12 workers → 6 days; 18 workers → 4 days
  8. 8. 3