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225
45 km/h×5 h.
Class 7 · English Medium · Cambridge · Mathematics
Ratio, proportion and algebra
Identify direct and inverse relationships.
About this lesson and its coverage
Original Kidemy Class 7 progression. This level has its own text, examples and questions. Curriculum versions share the progression; complete board-specific coverage still needs specification matching and additional material.
Learn the idea
Direct proportion keeps y/x constant. Inverse proportion keeps xy constant for nonzero values. Decide which model matches the situation before scaling; real workers or machines need not have identical productivity.
Worked example
If4 identical pumps take6 h,8 take3 h under ideal equal-rate conditions. Pump count×time remains24.
- Identify the quantities and restrictions.
- Show a method with units or symbols.
- Check and explain the result.
Your written practice
Show your working on paper. Check your answer, then choose Next.
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4
6×8÷12.
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63
7×9.
Write in your own words. A guardian or teacher should review this response.
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A nonzero fee remains at zero hours.
Explain the intercept.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
Pumps work at equal rates and do not interfere, with the same total job.
Name practical model assumptions.
Progress and browser storage
Notebook challenge, sources and further study
Apply the idea
Build tables for one direct and one inverse relationship and identify their constants.
Review with a guardian or teacher
- Use the stated evidence or givens.
- Show reasoning rather than only a result.
- Review and explain one correction.
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