Apuppy grew 8/12 of a foot in two months the first month the puppy grew 5/12 of a foot. how much did the puppy griw the second month? ? do a have to add or subtract

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?