InterviewSolution
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InterviewSolution
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A bag contains `n+1`coins. If is known that one of these coins shows heads onboth sides, whereas the other coins are fair. One coin is selected at randomand tossed. If the probability that toss results in heads is 7/12, then findthe value of `ndot`A. 3B. 4C. 5D. none of these |
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Answer» Correct Answer - C Let `E_(1)` denote the event a coin with two heads is selected and `E_(2)` denote the event a fair coin is selected . Let A be the event the toss results in head. Then., `P(E_(1))=(1)/(n+1),P(E_(2))=(n)/(n+1),P(A//E_(2))=1` and `P(A//E_(2))=1//2`. `therefore P(A)=P(E_(1))P(A//E_(1))+P(E_(2))P(A//E_(2))` `implies (7)/(12)=(1)/(n+1)xx1+(n)/(n+1)xx(1)/(2)` `implies 12+6n=7n+7 implies n=5` |
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