I have two questions to answer which im struggling with, could anyone pls help? the questions are:

1) In a market research project a local authority has requested the evaluation of the demand for a library. Visitors to the library stay for a mean of 3 hours with a standard deviation of 1.8 hours. Within a sample of 1000 visitors how many can be expected to visit the library for (a) less than 2 hours (b) more than 5 hours (c) between 2 and 5 hours. Assume that the distribution is normally distributed.

2) In order to estimate the percentage of dwellings which have a smoke alarm in the northwest to within 1% for a 95% confidence level a pilot survey was carried out. From a random sample of 30 dwellings, 12 were found to have a smoke alarm installed. How many houses need to be sampled in the main survey?

Thanks!