Katy bought a candy bar and shared it with her two sisters. she gave her youngest sister 1/4 of the candy bar. her older sister received 1/3 of the candy bar. how much of the candy bar did katy keep?

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?