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Question
A bag contains 8 red and 5 white balls. Three balls are drawn at random. Find the probability that all the three balls are red
Solution
Given that: Number of red balls = 8
Number of white balls = 5
P(all the three balls are red) = `(""^8C_3)/(""^13C_3)`
= `((81)/(3!5!))/((131)/(3!10!))`
= `(8!)/(3!5!) xx (3!10!)/(13!)`
= `(8 xx 7 xx 6 xx 51)/(5!) xx (10!)/(13 xx 12 xx 11 xx 10!)`
= `(8 xx 7 xx 6)/(13 xx 12 xx 11)`
= `28/143`
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