How do i factor out the coefficient of the variable 3/5k = 3/10

Roger could feed 5 walruses with 4 kilograms of fish. how many walruses could he feed with 7.2 kilograms of fish?

Alex measured the length of an item to be 3.7 cm. the actual length is 3.5 cm. what is alex’s percent error?

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?