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Three integers are chosen at random without replacement from the first 20 positive integers.  What is the probability that their product is even?

 Jun 29, 2020
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For the product to be even there must be at least one even integer.

 

Probability of no even integers p0 = (10/20)*(9/19)*(8/18)

 

Hence probability of at least one even integer = probability of even product    p = 1 - (10/20)*(9/19)*(8/18)

 

(Edited to make more sense!  Thanks EP).

 Jun 29, 2020
edited by Alan  Jun 30, 2020

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