JCECE Engineering JCECE Engineering Solved Paper-2006

  • question_answer
    A problem in mathematics is given to three students \[A,\,\,\,B,\,\,\,C\] and their respective probability of solving the problem is \[\frac{1}{2},\,\,\,\frac{1}{3}\] and\[\frac{1}{4}\]. Probability that the problem is solved, is:

    A) \[\frac{3}{4}\]                                   

    B) \[\frac{1}{2}\]

    C) \[\frac{2}{3}\]                                   

    D) \[\frac{1}{3}\]

    Correct Answer: A

    Solution :

    \[P({{E}_{1}})=\frac{1}{2},\,\,P({{E}_{2}})=\frac{1}{3}\]and\[P({{E}_{3}})=\frac{1}{4}\] \[P({{E}_{1}}\cup {{E}_{2}}\cup {{E}_{3}})=1-P({{\bar{E}}_{1}})P({{\bar{E}}_{2}})P({{\bar{E}}_{3}})\] \[=1-\left( 1-\frac{1}{2} \right)\left( 1-\frac{1}{3} \right)\left( 1-\frac{1}{4} \right)\] \[=1-\frac{1}{2}\times \frac{2}{3}\times \frac{3}{4}=\frac{3}{4}\] Note: If the events \[{{E}_{1}},\,\,\,{{E}_{2}}\] and \[{{E}_{3}}\] are independent, then \[{{\bar{E}}_{1}},\,\,\,{{\bar{E}}_{2}}\] and \[{{\bar{E}}_{3}}\] are also independent.


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