A green roof is like a traditional roof but covered with plants. Plants used for green roof cost $0.75 per square foot. The roof at the right is 40 feet long. How much does it cost to cover both sides of the roof? Justify your answer.

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?