Recall Problem 5.1.9 where glass sheets have a N(3.00, 0.122) distribution. (a) What is the probability that

Question:

Recall Problem 5.1.9 where glass sheets have a N(3.00, 0.122) distribution.
(a) What is the probability that three glass sheets placed one on top of another have a total thickness greater than 9.50 mm?
(b) What is the probability that seven glass sheets have an average thickness less than 3.10 mm?