Answer :
Fred has the highest success rate with 75%, making him the winner.
To determine the winner of the foul shooting contest, we need to calculate the free throw success rate for each player. The player with the highest success rate (percentage of shots made) is the winner.
Mario's success rate: 11 out of 16 tries = 68.75%
Plato's success rate: 10 out of 15 tries = 66.67%
Fred's success rate: 15 out of 20 tries = 75%
Sam's success rate: 9 out of 17 tries = 52.94%
Karen's success rate: 15 out of 21 tries = 71.43%
Comparing these percentages, Fred is the winner of the foul shooting contest with the highest success rate of 75%.