{loadmoduleid 241}
problem:
A car is going at at speed of 100 mph. It takes 10 minutes to go the shopping center.
How long does it take the same car if it is going at a speed of 80 mph?
{loadmoduleid 234}
answer:
1. step: proportion
* 100 mph – 10 minutes
: 80 mph – x minutes
2. step: which proportion?
↓less speed ↑more minutes = inverse proportion
3. step: formula
x = 10 * 100
80
x = 12,5 minutes (12 minutes 30 seconds)
4. step: answer
It takes the car 12,5 minutes to the shopping center.