Railways R.R.C. (Chennai) Solved Paper Held on 17-11-2013

  • question_answer A student has 60% chance of passing in English and 54% chance of passing in both English and Maths. What is the percentage probability that he will fail in maths?

    A) 12                                

    B) 36

    C) 4                                 

    D) 10

    Correct Answer: D

    Solution :

    Let probability of passing in English and Math are P & P (B). Then, here \[P\,\,(A)=60%\] \[P\,\,(A\cap B)=54%\] \[P\,\,(A\cap B)=P\,\,(A)\times P\,\,(B)\] \[54=60\times P\,\,(B)\] \[\Rightarrow \]   \[P\,\,(B)=0.9\] \[P(B)=90%\] Hence, the % probability that he will fail in Maths \[=P\,\,(B)\] \[=100-90\] = 10%


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