Which is not equivalent to Ax + By = C?

You purchased 8 pounds 10 ounces of candy from a candy shop. you want to split it equally among 3 classrooms at a local school.

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

Awasher and a dryer cost $701 combined. the washer costs $51 more than the dryer. what is the cost of the dryer?