A discount retail store has two outlets in Houston, with a common warehouse. Customer requests are phoned to the warehouse for pickup. Two items, a and b, are featured in a special sale. The number of orders in a day from store A is Poisson (30); from store B, the nember of orders is Poisson (40).
For store A, the probability an order for a is 0.3, and for b is 0.7.
For store B, the probability an order for a is 0.4, and for b is 0.6. What is the probability the total order for item b in a day is 50 or more?
Pfeiffer, Applied Probability, 15.3 Problems on Random Selection, exercise 23