A small balloon is released at a point 150 feet away from an observer who is on level ground. If the balloon goes straight up at the rate of 8 ft/sec, how fast is the distance from the observer to the balloon increasing when the balloon is 50 ft. high

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?