Evalute each expression for s=4 and t=8
1) (s+t)^3
2) s^4+t^2+5/2
3) (st)^2/(st^2)

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $36.98. find the probability that a randomly selected bill will have an amount greater than $173, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?