RAJASTHAN ­ PET Rajasthan PET Solved Paper-2007

  • question_answer
    Let A and B be two events such that\[P\overline{(A\cup B)}=\frac{1}{6},P(A\cap B)=\frac{1}{4}\]an\[P(\overline{A})=\frac{1}{4},\]where A stands for complement of event A. Then, events A and B are

    A)  mutually exclusive and independent

    B)  independent but not equally likely

    C)  equally likely but not independent

    D)  equally likely and mutually exclusive

    Correct Answer: B

    Solution :

     Given, \[P(\overline{A\cup B})=\frac{1}{6},P(\overline{A\cap B})=\frac{1}{4},P(\overline{A})=\frac{1}{4}\] \[\because \] \[P(\overline{A\cup B})=\frac{1}{6}\] \[\Rightarrow \] \[1-P(A\cup B)=\frac{1}{6}\] \[\Rightarrow \]\[1-P(A)-P(B)+P(A\cap B)=\frac{1}{6}\] \[\Rightarrow \] \[P(\overline{A})-P(B)+P(A\cap B)=\frac{1}{6}\] \[\Rightarrow \] \[-P(B)=\frac{1}{6}-\frac{1}{4}-\frac{1}{4}\] \[\Rightarrow \] \[P(B)=\frac{1}{3}\] and \[P(A)=\frac{3}{4}\] Clearly,   \[P(A\cap B)=P(A).P(B)\] So, the events A and B are independent events but not equally likely.


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