From the intersection for the following sets. x = {0,10,100,1000} y = {100,1000} x n y = (the n is not the letter n it is a symbol i cannot find on my keyboard so i'm sorry)

Having a hard time understanding this question (see attachment).

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?

What is the correct decimal form of 12%