Ihave a test due very soon! brine is a solution of salt and water. if a tub contains 50 gallons of a 5% solution of brine, how much water must evaporate to change it to an 8% solution? in advance

The sum of the product of 4 and x and the product of 7 and y is 61. the sum of the product of 12 and x and the product of 21 and y is 61. what are the values of x and y?

If 25% of y is 30, what is 60% of y?

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?