Probability that a Large Shipment is Accepted or Not Accepted due to Defective Items

Problem
A stationery store has decided to accept a large shipment of ball-point pens if an inspection of 20 randomly selected pens yields no more than two defective pens.

1. Find the probability that this shipment is accepted if 5% of the total shipment is defective.
2. Find the probability that this shipment is not accepted if 15% of the total shipment is defective.

Solution