A and B likely to contradict each other in stating same fact?












0












$begingroup$


A speaks truth in $75%$ cases and B in $80%$ cases. In what percentage of cases are they likely to contradict each other in stating the same fact?



(a) $70%$ (b)$35%$



(c) $25%$ (d)$20%$



what i have tried:

I would like to show about what i think, If QA is in Yes/No both A and B answer behave in similar to Exclusive-OR where agree$=0$ and disagree$=1$

$$begin{array}{l|l|l}
text{A} & text{B} & text{Fact} \ hline
T & T & text{agree} \ hline
T & F & text{disagree} \ hline
F & T & text{disagree} \ hline
F & F & text{agree}
end{array}$$
Percentage of cases where they are likely to contradict each other=$80%-75%=5%$

because till $75%$ A speaks the truth and even B speaks truth

After $75%$ A speaks false and B speaks truth and after $80%$ both A & B speaks false

and so the answer is $5%$ which is not there in option can any please help me this problem?










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    A speaks truth in $75%$ cases and B in $80%$ cases. In what percentage of cases are they likely to contradict each other in stating the same fact?



    (a) $70%$ (b)$35%$



    (c) $25%$ (d)$20%$



    what i have tried:

    I would like to show about what i think, If QA is in Yes/No both A and B answer behave in similar to Exclusive-OR where agree$=0$ and disagree$=1$

    $$begin{array}{l|l|l}
    text{A} & text{B} & text{Fact} \ hline
    T & T & text{agree} \ hline
    T & F & text{disagree} \ hline
    F & T & text{disagree} \ hline
    F & F & text{agree}
    end{array}$$
    Percentage of cases where they are likely to contradict each other=$80%-75%=5%$

    because till $75%$ A speaks the truth and even B speaks truth

    After $75%$ A speaks false and B speaks truth and after $80%$ both A & B speaks false

    and so the answer is $5%$ which is not there in option can any please help me this problem?










    share|cite|improve this question









    $endgroup$















      0












      0








      0


      1



      $begingroup$


      A speaks truth in $75%$ cases and B in $80%$ cases. In what percentage of cases are they likely to contradict each other in stating the same fact?



      (a) $70%$ (b)$35%$



      (c) $25%$ (d)$20%$



      what i have tried:

      I would like to show about what i think, If QA is in Yes/No both A and B answer behave in similar to Exclusive-OR where agree$=0$ and disagree$=1$

      $$begin{array}{l|l|l}
      text{A} & text{B} & text{Fact} \ hline
      T & T & text{agree} \ hline
      T & F & text{disagree} \ hline
      F & T & text{disagree} \ hline
      F & F & text{agree}
      end{array}$$
      Percentage of cases where they are likely to contradict each other=$80%-75%=5%$

      because till $75%$ A speaks the truth and even B speaks truth

      After $75%$ A speaks false and B speaks truth and after $80%$ both A & B speaks false

      and so the answer is $5%$ which is not there in option can any please help me this problem?










      share|cite|improve this question









      $endgroup$




      A speaks truth in $75%$ cases and B in $80%$ cases. In what percentage of cases are they likely to contradict each other in stating the same fact?



      (a) $70%$ (b)$35%$



      (c) $25%$ (d)$20%$



      what i have tried:

      I would like to show about what i think, If QA is in Yes/No both A and B answer behave in similar to Exclusive-OR where agree$=0$ and disagree$=1$

      $$begin{array}{l|l|l}
      text{A} & text{B} & text{Fact} \ hline
      T & T & text{agree} \ hline
      T & F & text{disagree} \ hline
      F & T & text{disagree} \ hline
      F & F & text{agree}
      end{array}$$
      Percentage of cases where they are likely to contradict each other=$80%-75%=5%$

      because till $75%$ A speaks the truth and even B speaks truth

      After $75%$ A speaks false and B speaks truth and after $80%$ both A & B speaks false

      and so the answer is $5%$ which is not there in option can any please help me this problem?







      probability permutations combinations percentages






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      asked Feb 5 '15 at 9:07









      CY5CY5

      160113




      160113






















          2 Answers
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          active

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          2












          $begingroup$

          The probability that they contradict each other is given by (TF, FT) as you mentioned in the table. Assuming both the speakers choose to speak truth or false independently, the probability can be calculated as follows-



          Suppose the probability A and B speak truth is given by $P_A$, $P_B$ respectively. Their probability of speaking false is given by $1-P_A$ and $1-P_B$, as speaking truth and false are mutually exclusive. The probability that they contradict each other is given by $P_A(1-P_B)+(1-P_A)P_B$






          share|cite|improve this answer









          $endgroup$





















            0












            $begingroup$

            Since it is not stated that they decide independantly whether or not to tell the truth, anything between $5%$ and $45%$ is possible.






            share|cite|improve this answer









            $endgroup$













            • $begingroup$
              how did you get $45%$?
              $endgroup$
              – CY5
              Feb 5 '15 at 9:35













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            2 Answers
            2






            active

            oldest

            votes








            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2












            $begingroup$

            The probability that they contradict each other is given by (TF, FT) as you mentioned in the table. Assuming both the speakers choose to speak truth or false independently, the probability can be calculated as follows-



            Suppose the probability A and B speak truth is given by $P_A$, $P_B$ respectively. Their probability of speaking false is given by $1-P_A$ and $1-P_B$, as speaking truth and false are mutually exclusive. The probability that they contradict each other is given by $P_A(1-P_B)+(1-P_A)P_B$






            share|cite|improve this answer









            $endgroup$


















              2












              $begingroup$

              The probability that they contradict each other is given by (TF, FT) as you mentioned in the table. Assuming both the speakers choose to speak truth or false independently, the probability can be calculated as follows-



              Suppose the probability A and B speak truth is given by $P_A$, $P_B$ respectively. Their probability of speaking false is given by $1-P_A$ and $1-P_B$, as speaking truth and false are mutually exclusive. The probability that they contradict each other is given by $P_A(1-P_B)+(1-P_A)P_B$






              share|cite|improve this answer









              $endgroup$
















                2












                2








                2





                $begingroup$

                The probability that they contradict each other is given by (TF, FT) as you mentioned in the table. Assuming both the speakers choose to speak truth or false independently, the probability can be calculated as follows-



                Suppose the probability A and B speak truth is given by $P_A$, $P_B$ respectively. Their probability of speaking false is given by $1-P_A$ and $1-P_B$, as speaking truth and false are mutually exclusive. The probability that they contradict each other is given by $P_A(1-P_B)+(1-P_A)P_B$






                share|cite|improve this answer









                $endgroup$



                The probability that they contradict each other is given by (TF, FT) as you mentioned in the table. Assuming both the speakers choose to speak truth or false independently, the probability can be calculated as follows-



                Suppose the probability A and B speak truth is given by $P_A$, $P_B$ respectively. Their probability of speaking false is given by $1-P_A$ and $1-P_B$, as speaking truth and false are mutually exclusive. The probability that they contradict each other is given by $P_A(1-P_B)+(1-P_A)P_B$







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Feb 5 '15 at 9:38









                CuriousCurious

                889516




                889516























                    0












                    $begingroup$

                    Since it is not stated that they decide independantly whether or not to tell the truth, anything between $5%$ and $45%$ is possible.






                    share|cite|improve this answer









                    $endgroup$













                    • $begingroup$
                      how did you get $45%$?
                      $endgroup$
                      – CY5
                      Feb 5 '15 at 9:35


















                    0












                    $begingroup$

                    Since it is not stated that they decide independantly whether or not to tell the truth, anything between $5%$ and $45%$ is possible.






                    share|cite|improve this answer









                    $endgroup$













                    • $begingroup$
                      how did you get $45%$?
                      $endgroup$
                      – CY5
                      Feb 5 '15 at 9:35
















                    0












                    0








                    0





                    $begingroup$

                    Since it is not stated that they decide independantly whether or not to tell the truth, anything between $5%$ and $45%$ is possible.






                    share|cite|improve this answer









                    $endgroup$



                    Since it is not stated that they decide independantly whether or not to tell the truth, anything between $5%$ and $45%$ is possible.







                    share|cite|improve this answer












                    share|cite|improve this answer



                    share|cite|improve this answer










                    answered Feb 5 '15 at 9:12









                    Hagen von EitzenHagen von Eitzen

                    279k23271502




                    279k23271502












                    • $begingroup$
                      how did you get $45%$?
                      $endgroup$
                      – CY5
                      Feb 5 '15 at 9:35




















                    • $begingroup$
                      how did you get $45%$?
                      $endgroup$
                      – CY5
                      Feb 5 '15 at 9:35


















                    $begingroup$
                    how did you get $45%$?
                    $endgroup$
                    – CY5
                    Feb 5 '15 at 9:35






                    $begingroup$
                    how did you get $45%$?
                    $endgroup$
                    – CY5
                    Feb 5 '15 at 9:35




















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