Rita, Peter, and Skeeter are penguins. They weigh 90 pounds altogether. Rita and Peter know they weigh the same amount. Peter and Skeeter know they weigh 68 pounds together. How much does Skeeter weigh?
R + 68 = 90 => R = 90 - 68 = 22
22 + S = 68 => S = 68 - 22 = 46
Skeeter weighs 46 pounds
