The amounts of time per workout an athlete uses a stairclimber are normally​ distributed, with a mean of 24 minutes and a standard deviation of 5 minutes. Find the probability that a randomly selected...

The amounts of time per workout an athlete uses a stairclimber are normally​ distributed, with a mean of
24minutes and a standard deviation of
5
minutes. Find the probability that a randomly selected athlete uses a stair climber for​

(a) less than
21
​minutes,

(b) between
24
and
32
minutes

(c) more than
40
minutes.