The amounts of time per workout an athlete uses a stairclimber are normallydistributed, with a mean of 24 minutes and a standard deviation of 7 minutes. Find the probability that a randomly selected athlete uses a stairclimber for

(a) less than 21 minutes, (b) between 24 and 31 minutes, and(c) more than 40 minutes.

(a) The probability that a randomly selected athlete uses a stairclimber for less than 21 minutes is nothing.

(Round to four decimal places asneeded.)