Class 8 · Ganita Prakash
Unit 10 · Class 8Ganita Prakash
Proportional Reasoning-2
Inverse variation, compound proportion, time-and-work.
Lessons
3 concepts
- 1Inverse Variation ExamplesMore workers → less time. Faster speed → less time. Product of quantities is constant.
- 2Time & Work SetupAssume total work = LCM of days. Worker's rate = total/days. Combined = sum. Time = total/combined.
- 3Compound ProportionMultiple factors: e.g., 3 men build 10m wall in 6 days. How long for 6 men, 20m? Adjust each factor proportionally.
Skills to practise