PEAZIT Aha card
Go straight to resources ↓Inverse proportion: the product stays fixed
In inverse proportion, x · y is constant. Twice as many equally productive workers need half the time for the same divisible task.
| Expression | Meaning |
|---|---|
| 4 × 6 = 24 | Four workers for six hours provide 24 worker-hours. |
| 8 × t = 24 | The same work is shared by eight workers. |
| t = 3 | 24 divided by 8 gives three hours. |
One worked example
- 4 × 6 = 24Four workers for six hours provide 24 worker-hours.
- 8 × t = 24The same work is shared by eight workers.
- t = 324 divided by 8 gives three hours.
Watch out: Real work may not divide perfectly; waiting and coordination can break the model. A decreasing relationship alone is not inverse proportion.
Goal, prerequisites and card origin
What you will learn: Solve a fixed-work problem with equally productive workers.
What you need first: Multiplication, division and the meaning of a product.
An original PEAZIT working card. Independent expert review and effectiveness testing have not yet taken place. · v1
Show connections
In inverse proportion, x · y is constant. Twice as many equally productive workers need half the time for the same divisible task.