An engineer is going to redesign an ejection seat for an airplane. The seat was designed for pilots weighing between 150 lb and 201 lb. The new population of pilots has normally distributed weights with a mean of 160lb and a standard deviation of 27.8lb.

a) If a pilot is randomly selected, find the probability that his weight is between 150 lb and 201 lb.

b)If 40 different pilots are randomly selected, find the probability that their mean weight is between 150 lb and 201 lb.