Resting heart rate was measured for a group of subjects; the subjects then drank 6 ounces of

Question:

Resting heart rate was measured for a group of subjects; the subjects then drank 6 ounces of coffee. Ten minutes later their heart rates were measured again. The change in heart rate followed a normal distribution, with a mean increase of 7.3 beats per minute and a standard deviation of 11.1. Let Y denote the change in heart rate for a randomly selected person. Find
(a) Pr{Y > 10}
(b) Pr[Y> 20}
(c) Pr{5 < Y < 15}