The National Association of Realtors estimates that 25% of all homes purchased in 2004 were considered investment properties. If a sample of 300 homes sold in 2004 is obtained what is the probability that at least 100 homes are going to be used as investment property?

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?