Answer to Question #91605 in Statistics and Probability for Margaret

Question #91605

Suppose you just received a shipment of twelve televisions. Three of the televisions are defective. If two televisions are randomly selected, compute the probability that both televisions work. What is the probability at least one of the two televisions does not work?

Expert's answer

the probability that the first selected TV is working 9/12=3/4

the probability that the second selected TV is working (9-1)/(12-1)=8/11

probability that both televisions work (3/4)*(8/11)=24/44=6/11

probability at least one of the two televisions does not work 1-(6/11)=5/11