A chef is trying to select 4 broccoli plants for a dinner sa

A chef is trying to select 4 broccoli plants for a dinner, sadly 20% of the shipment has been eaten by pests. He will keep checking broccoli until he finds 4 broccoli plants that are not eaten by pests, Find the probability that he will have to throw out 3 plants.

Solution

P( Probability that he will have to throw out 3 plants ) = He must check seven plants to find 4 broccoli plant that are not eaten by pests, with 4 success, 3 failure = (0.80)^4 * (0.20)^3 = 0.0032768