Records indicate that the average arrival rate of customers at a gasoline service station is 4.3
arrivals every 10 minutes. The arrivals are independent and random.
a. 5 What is the probability that less than 7 customers arrive in a 10 minute period ? 0.8558
b. 5 What is the probability that more than 8 will arrive in the next half hour ?
c. 5 A half hour has passed and 7 customers have arrived, what is the probability that if you
keep counting for another half hour there will be at least 15 in total?
On Dec 2, 2008 in Barrie 12 percent of customers purchase premium grade gasoline.
80 percent purchase regular grade gasoline and the rest purchased mid-grade gasoline. The
purchases are independent of each other.