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प्रश्न
Two balls are drawn from an urn containing 3 white, 5 red and 2 black balls, one by one without replacement. What is the probability that at least one ball is red?
उत्तर
P(atleast one ball is Red)
`= 1 - P (No ball is red)`
`= 1-P (Non red)xx p(No Red II)`
`= 1 - 5/10xx 4/9 = 1- = 20/90 = 7/9`
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