Question: After completing a study, the Chicago O-Hare Airport managers have concluded that the time to get passengers loaded onto an airplane is normally distributed with a mean equal to 15 minutes and a standard deviation equal to 3.5 minutes.

a. What is the probability that a randomly selected flight will take less than 9 minutes to board?

b. What is the probability that a randomly selected flight will take between 12 and 16 minutes to board?

c. What is the probability that a randomly selected flight will take more than 18 minutes to board?

d. At Chicago O’Hare Airport, employees can get incentive-based rewards for getting flights to board quickly. For every flight that boards in the top 10% of times (top meaning lower times – i.e. the quicker the better), employees working that flight at the gate service counter will get an extra $20 on their paycheck. What is the slowest boarding time that an employee may have and still be within the top 10%?