The time per workout an athlete uses a stairclimber is normally distributed, with a mean of 20 minutes and a standard deviation of 5 minutes.  An athlete is randomly selected.

1. Find the probability to three significant figures that the athlete uses a stairclimber for less than 17 minutes.  {#1}
   
2. Find the probability to three significant figures that the athlete uses a stairclimber between 20 and 28 minutes.  {#2}
   
   
3. Find the probability to three significant figures that the athlete uses a stairclimber more than 30 minutes.  {#3}