The annual rainfall (in inches) in a certain region is normally distributed with mean?

The annual rainfall (in inches) in a certain region is normally distributed with mean? and variance 16.

a)over the years,it is found that the probability is 0.02 that the annual rainfall is less than 32 inches. Find the mean of the annual rainfall.

b)Assume the rainfalls in different years are independent . Find the probability that in one of the next 4 years the rainfall will exceed 48 inches