Develop a 95% confidence interval estimate of the population mean sales price and population mean number of days to sell for Gulf View condominiums

Need Help with some statistic questions. 

1. Develop a 95% confidence interval estimate of the population mean sales price and population mean number of days to sell for Gulf View condominiums. Interpret your results.
2. Assume the branch manager requested estimates of the mean selling price of Gulf View condominiums with a margin of error of $40,000 and the mean selling price of No Gulf View condominiums with a margin of error of $15,000. Using 95% confidence, how large should the sample sizes be for each?