In a box of 24 iPods, 3 are defective. If 3 are sold, find the probability that all are defective. Would you consider this event likely or unlikely to occur?

2 Answers
Apr 24, 2017

Very unlikely to occur.

Explanation:

3/24 are defective, so the probability of selling 3 all defective is 3/24 * 2/23 * 1/22 = 1/2024, we remove 1 from the defective ipads and one from the total each time.

Apr 24, 2017

1/2024 (unlikely).

Explanation:

Selling three iPods out of a box of 24 can be said as picking 3 out of 24, without order mattering. This can be written as C(24,3)=(24!)/(3!(24-3)!)=(24!)/(3!21!)=2024. As C(3,3) is obviously one (If order doesn't matter, D1, D2, D3 is the only option), the probability is 1/2024, which is obviously very unlikely.