Q78 / 160 · AP EAMCET 2022 (07 Jul Shift 2) · Mathematics

A person $P$ speaks truth in $75 \%$ cases and another person $R$ in $80 \%$ cases. Then, the probability that they likely to contradict each other in narrating the same event is

  • Correct answer
    A
    $\frac{7}{20}$
  • B
    $\frac{7}{10}$
  • C
    $02$
  • D
    $0.3$

Solution

' Favourable cases - Case I $A$ speaks truth, $B$ does not Case II $B$ speaks truth, $A$ does not $\therefore$ Probability $=\frac{3}{4} \times \frac{1}{5}+\frac{1}{4} \times \frac{4}{5}=\frac{7}{20}$

Hence, the correct answer is option: 'A'.

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