Class 8 · Chapter 10
Proportional Reasoning-2
Inverse variation, compound proportion, time-and-work.
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Ganita Prakash · Class 8 Part 2 (2026-27)
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Detailed theory
More workers → less time. Faster speed → less time. Product of quantities is constant.
Key concepts & formulas
01
**Inverse variation**: ; .
02
**Compound proportion**: multiple ratios combined.
03
Time-and-work: if finishes in days, rate is per day.
04
Combined rate: per day (when both work together).
05
Total time = (for two workers).