It is known that from a lot of 100 computers there are 20 defective ones. 5 of these computers are selected at random and tested. Find the probability that only 2 of the 5 are defective.
Let "X=" the number of defective computers out of randomly selected 5 computers:
"=\\dfrac{\\dfrac{20!}{2!(20-2)!}\\cdot \\dfrac{80!}{3!(80-3)!}}{\\dfrac{100!}{5!(100-5)!}}"
"=\\dfrac{190\\cdot82160}{75287520}\\approx0.207344"
The probability that only 2 of the 5 are defective is "0.207344."
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