Archibald and his brother are playing tennis against each other. Archibald has won 12 games and his brother has won 18. What percentage of games has Archibald won?
##Solution## They have played 30 total games because 12 + 18 = <<12+18=30>>30
The proportion won by Archibald is .4 because 12 / 30 = <<12/30=.4>>.4
The percentage he has won in 40% because .4 x 100% = 40%
#### 40