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.