so i got reported over 5 times because im giving free points imagin which is technically me getting reported for being generous which is weird they are probably just jealous they didn't get free points but an wh PPOINT

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?