Q25 of 99 Page 33

Mark the correct alternative in the following:

The probability of selecting a male or a female is same. If the probability that in an office of n persons (n – 1) males being selected is , the value of n is


Given:


P(females)=p(males)=1/2


p(x=n-1) =


n=?


p(x=n-1) = nCn-1 pn-1 q1


Since p=q


p(x=n-1)= n pn-1q


=n pn-1p


=npn


=n





comparing LHS anr RHS


we have,


n=12

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