If sn=Σ what is the value of ?

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?

It says factor each expression 49x-28?

There are 45 questions on your math exam. you answered 810 of them correctly. how many questions did you answer correctly?