Andy bought a game system on sale for $194.70. it was originally priced at $220.
what is the percent of the discount on this game system?

The game system was bought by Andy on sale at $194.70
Original price of the game system bought by Andy is $220
Amount of discount Andy got on the game system = (220 - 194.7) dollars
                                                                                 = 25.3 dollar
The question needs the percentage of discount that Andy got while buying the game system.
Then
The percentage of discount andy got on the game system = [(25.3/220) * 100]
                                                                                              = 11.5
Then Andy got 11.5% discount while buying the game system.

Yea they are simplyfiy the ratios