Need help with statistics for business and economics about a local health care company

A local health care company has asked you to determine the average costs of elderly day-care. They provided you with a random sample of 10 facilities. This shows a mean of $250 per week, with a standard deviation of $25. Note that the population parameters are unknown.
a. What is the point estimate for the population mean?
b. What is the 90% confidence interval for the population mean?
As you are presenting your results to the company, you realize that they have no idea what a confidence interval is.
c. Explain how the confidence interval should be interpreted, using your answer (b) as point of departure.