What is the probability that no one is waiting or being served in ...

[mmm]

What is the probability that no one is waiting or being served in the express checkout line?
 
  What will be an ideal response?

Question 2

You are in charge of arranging the catering for a company meeting. Your company is responsible for paying for all meals ordered, so you don't want to order too many.
 
  Suppose that the expected number of people for the meeting is 84, with a standard deviation of 4 people. What is the fewest number of meals should you order so that the probability of having more people than meals is 5?

[scrocafella]

Answer to Question 1

P(Express line is empty) = P(Y = 0 ) = 0.30

Answer to Question 2

P(X > k) = 0.05  PZ > (k - 84 ) / 4 = 0.05  (k - 84 ) / 4 = 1.645  k = 90.58  91 meals