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1)

Of the three independent events  E1,E2andE3  , the probability that only E1 occurs is α , only E2 occurs is β   and only E3 occurs is γ .Let  the probability p that none  of E1E2 or E3 occurs satisfy the equations   (α2β),p=αβ and   (β3γ)   p=2βγ  .All the given probabilities are assumed to lie in the interval (0,1)

 Then, probability of occurrence of E1/ probability of occurrence  of Eis equal to


A) 5

B) 4

C) 2

D) 6

Answer:

Option D

Explanation:

Concept involved

 For   the events to be independent.

 P(E1E2E3)=P(E1)P(E2)P(E3)

P(E1¯E2¯E3)=P

                                    (on;y E1 occurs)

 =   P(E1).(1P(E2))(1P(E3))

 let x,y,z are probability of  E1E2 and E3 respectively

              α   = x(1-y)(1-z)   ......(i)

                                 β    = (1-x).y(1-z)         ......(ii)

                                  γ  = (1-x)(1-y) z     ..........(iii)

   p = (1-x) (1-y) (1-z)        ..........(iv)

 Given   (α2β)p=αβ 

  and     (β3γ)p=2βγ    .......(v)

 From above equations

 x=2y  and y=3 z

    x=6z   =  xz=6