Hello can anyone help me?

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.

Answer asap and if you do you will get brainliest. catherine buys a gallon of ice cream from the store. after taking it home, she eats a fifth of a gallon of ice cream. her sister eats some of the ice cream as well. if two-thirds of the original amount of ice cream is left, then what fraction of a gallon of ice cream did her sister eat?

You eat $0.85 for every cup of hot chocolate you sell. how many cups do you need to sell to earn $55.25