Answer:
15
Step-by-step explanation:
Set up two equal proportions to solve this.
[tex]\frac{120}{800} = \frac{x}{100}[/tex]
Now cross-multiply!
120*100 = 800x
Simplify:
12000 = 800x
Divide both sides by 800:
15 = x
So out of 100 people, 15 are running for a cause. That's 15%.
(Check afterwards: does that answer make sense? Well, if we simplify, 120/800 = 12/80 = 3/20 = 1.5/10. So now we checked to be sure we didn't make an error in arithmetic!)
