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← 1.4 Compound Proportions and Rates of Work

A and B working together

Mathematics · Grade 9 · about 40 minutes

Add rates. A at 1/6 per hour and B at 1/3 per hour paint 1/2 classroom per hour, so they finish in 2 hours.

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Other lessons in this sub-strand

  1. What a proportion is
  2. Divide a quantity in the ratio 2:3
  3. Three-part ratio 2:3:5
  4. A share as a fraction of the whole
  5. Relating different proportional parts
  6. Compound proportion when B already matches
  7. Compound proportion when B must be scaled
  8. Rate of work: job per hour
  9. More workers, less time
  10. A and B working together
  11. Kenya word problems: share, mix, paint
  12. Review: parts, compound, rates