2. Solved Papers
  3. BCECE Engineering

BCECE Engineering BCECE Engineering Solved Paper-2003

  • question_answer
    If the probability of X to fail in the examination is 0.3 and that for Y is 0.2, then the probability that either X or Y fail in examination is:

    A)  0.5                                        

    B)                   0.44

    C)                   0.6                                        

    D)                   none of these

    Correct Answer: B

    Solution :

    Key Idea: The probability of either \[X\]or \[Y\]fails in the examination is \[P(X\cup Y)=P(X)+P(Y)-P(X\cap Y).\] Give that \[P(X)=0.3,P(Y)=0.2\] \[\therefore \]\[P(X\cup Y)=P(X)+P(Y)-P(X\cap Y)\] Since, the failure of \[X\] does not depends on the failure of \[Y,\]so \[X\]and \[Y\]are independent events. \[\therefore \]\[P(X\cup Y)=P(X)+P(Y)-P(X)\cap P(Y)\] \[=0.3+0.2-0.3\times 0.2\] \[=0.5-0.06\] \[=0.44\]


You need to login to perform this action.
You will be redirected in 3 sec spinner