A shipment of 20 TV tubes contains 16 good tubes and 4 defective tubes. Three tubes are chosen successively and at random each time and are also tested successively. What is the probability that:

(a) The third tube is good if the first two were found to be good?

(b) The third tube is defective if the first was found to be good and the second defective.

(c) The third tube is defective if the first was found to be defective and the second was found to be good.

(d) The third tube is defective if one of the other two was found to be good and the other was found to be defective.

(Hint: Denote by Di and Gi the events that the ith tube is defective or good, respectively, i = 1, 2, 3.)

Answer rating: 100% (QA)

Answers and Explanation a Given that the first two tubes were found to be good there are 16 good tub... View the full answer