What are some expressions that equal 2v2

Based on what i know about mean, this doesn't add up.

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?

Simplify 24÷(-2)(3)+7 a. -29 b. 3 c. 11