InterviewSolution
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InterviewSolution
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Of the three independent event `E_(1),E_(2)` and `E_(3)`, the probability that only `E_(1)` occurs is `alpha`, only `E_(2)` occurs is `beta` and only `E_(3)` occurs is `gamma`. If the probavvility p that none of events `E_(1), E_(2)` or `E_(3)` occurs satisfy the equations `(alpha - 2beta)p = alpha beta` and `(beta - 3 gamma) p = 2 beta gamma`. All the given probabilities are assumed to lie in the interval (0, 1). Then, `("probability of occurrence of " E_(1))/("probability of occurrence of " E_(3))` is equal to |
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Answer» Let `P(E_(1))=x,P(E_(2))=y and P(E_(3))=z,then` `(1-x)(1-y)(1-z)=p` `x(1-y)(1-z)=alpha,` `(1-x)y(1-z)=beta,` `(1-x)(1-y)(z)=gamma` `So, (1-x)/(x)=(p)/(alpha)=x=(alpha)/(alpha+p),` Similarly, `z=(gamma)/(gamma+p).` So, `(P(E_(1)))/(P(E_(3)))=((alpha)/(alpha+p))/(gamma/gamma+p)=((gamma+p)/(gamma))/((alpha+p)/(alpha))=(a+p/gamma)/(1+(p)/(alpha))` Also given `(alphabeta)/(alpha-2beta)=p=(2betagamma)/(beta=3gamma)impliesbeta=(5alphagamma)/(alpha+4gamma)` Substituting in given relation `(alpha-2((5alpha gamma)/(alpha+4gamma)))p=(alphaxx5alphagamma)/(alpha+4gamma)` `or ((p)/(gamma)+1)=6((p)/(alpha)+1)` `or ((p)/(gamma+1))/((p)/(alpha)+1)=6.` |
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