Over which of the following intervals does the flow rate increase by the greatest amount?
A. x = 0 to x = 1
B. X = 2 to x = 3
C. X = 4 to x = 5
D. x = 8 to x = 9

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?