{loadmoduleid 241}
problem:
6 caterpillars need 20 days to cut a canal.
How many caterpillars are needed to cut the canal within 15 days?
{loadmoduleid 234}
answer:
1. step: proportion
* 20 days – 6 caterpillars
: 15 days – x caterpillars
2. step: which proportion?
↓ less days ↑more caterpillars = inverse proportion
3. step: formula
x = 6 * 20
15
x = 8 caterpillars
4. step: answer
8 caterpillars are needed.