amyhussein wrote:If we have 8 numbers from 1 to 8, we r choosing 4 numbers . What is the probability that the chosen numbers are 1,2,4,5?
Good numbers are 1, 2, 4, and 5.
P(1st number is good) = 4/8. (Of the 8 numbers, any of the 4 good numbers may be selected.)
P(2nd number is good) = 3/7. (Of the 7 remaining numbers, any of the 3 remaining good numbers may be selected.)
P(3rd number is good) = 2/6. (Of the 6 remaining numbers, either of the 2 remaining good numbers may be selected.)
P(4th number is good) = 1/5. (Of the 5 remaining numbers, the 1 remaining good number must be selected.)
Since we want all of these events to happen together, we multiply the probabilities:
4/8 * 3/7 * 2/6 * 1/5 = 1/70.
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