Times for a surgical procedure are normally distributed. There are two methods. Method A has a mean

Question:

Times for a surgical procedure are normally distributed. There are two methods. Method A has a mean of 28 minutes and a standard deviation of 4 minutes, while method B has a mean of 32 minutes and a standard deviation of 2 minutes.
(a) Which procedure is preferred if the procedure must be completed within 28 minutes?
(b) Thirty-eight minutes?
(c) Thirty-six minutes? Explain your reasoning fully.