Iam planting 50 apple trees and 30 peach trees. i want the same number and type of trees per row. what is the maximum number of trees i can plant per row?

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?