Pass Check: Proportion
Direct and inverse proportion: spotting the type and using the correct equation.
Direct proportion
As one quantity increases, the other increases at the same rate; y = kx.
Inverse proportion
As one quantity increases, the other decreases; y = k/x.
Constant of proportionality (k)
The fixed number linking the two quantities in a proportion equation.
Proportional graph
Direct proportion gives a straight line through the origin; inverse proportion gives a curve.
Quick check
Mixed quiz
1. 5 workers can complete a job in 16 days. How many days would 10 workers take, assuming the same rate?
2. Share GBP 84 in the ratio 4:3. Find the larger share.
3. 4 workers can complete a job in 15 days. How many days would 8 workers take, assuming the same rate?
4. Share GBP 108 in the ratio 10:3. Find the larger share.
5. 5 workers can complete a job in 13 days. How many days would 10 workers take, assuming the same rate?
6. 6 workers can complete a job in 17 days. How many days would 12 workers take, assuming the same rate?
7. A 400g box of cereal costs £2.00 and a 600g box costs £3.30. Which is better value per gram?
8. 4 workers can complete a job in 12 days. How many days would 8 workers take, assuming the same rate?