the times per workout an athlete uses a stair climber are normally distributed with a mean of 20 minutes and standard devation of 5 minutes what percebtage of athletes use the stair climber for less than 18 minutes

So what you need to do is get the total number of medals find the % medals of USA over total medals use the % to find the degrees by multiply the % to 360. And you can do it like this: 31+20+6+6+6 = 69 31/69 = 44.9% 44.9% * 360 = 161.7 degree. I hope this can help you greatly