15 tv were shipped 4 were defective if 2 tv's were random selected compute the possibility of both tv's working and the probability that at least one of the 2 tv does not work

Answer 1

If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events.

11/15 * 11/15 = ?

That means one or both do not work.

One not work = 4/15 * 11/15 = ?

Both not work = 4/15 * 11/15 = ?

Either-or probabilities are found by adding the individual probabilities.