The probability that both televisions work is?

Question

Suppose you just received a shipment of

fifteen

televisions.

Four

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?

Answer 1

The probability that the first TV works is 11/15. Now we are left with 14 TV's, 10 of which work, so the probability that the second TV works is 10/14. The probability that both of them work will then be (11/15)(10/14) = 110/210, or about 0.5238 (52.38%).