In a photographic process, the developing time of prints may be looked upon as a random variable having the normal distribution with = 15.40

In a photographic process, the developing time of prints may be looked upon as a random variable having the normal distribution with µ = 15.40 seconds and σ = 0.48 second. Find the probabilities that the time it takes to develop one of the prints will be
(a) At least 16.00 seconds;
(b) At most 14.20 seconds;
(c) Anywhere from 15.00 to 15.80 seconds.