{loadmoduleid 241}
problem:
15 workmen need 20 days to build a new street.
How many workmen are needed to build the house in 30 days?
{loadmoduleid 241}
answer:
1. step: proportion
* 20 days – 15 workmen
: 30 days – x workmen
2. step: which proportion?
↑more days ↓less workmen = inverse proportion
3. step: formula
x = 15 * 20
30
x = 10 workmen
4. step: answer
10 workmen are needed.