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InterviewSolution
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There are two red, two blue, two white, and certain number (greaterthan 0) of green socks n a drawer. If two socks are taken at random from thedrawer4 without replacement, the probability that they are of the same coloris 1/5, then the number of green socks are ________. |
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Answer» Correct Answer - D Let the number of green socks be `x gt 0`. E: Two socks drawn are of the same color implies P(E) = P(R R or B B or W W or G G) `=(3)/(.^(6+x)C_(2)) + (.^(x)C_(2))/(.^(6+x)C_(2))` `=(6)/((x + 6)(x + 5))+(x (x-1))/((x+6)(x+5)) = (1)/(5)`(given) `implies 5(x^(2) - x + 6) = x^(2) + 11x + 30` `or 4x^(2) - 16x = 0` or x = 4 |
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