If a game's price went down from $60.00 to $42.00, what is the percent of the decrease?

The answer is 30%.

This is because 60-42 is 18.  
Now our new problem is what percent of 60 is 18?

 x=18%. 
Now we have two simple equations:
1) 60=100%
2) x=18%
Where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:
60/x=100%/18%
x=18%

Hope this helps!!