Aptitude | Probability | Question 10
Ram speaks truth in 3/4 of cases and Shyam in 4/5 of cases. In what percent of cases while narrating the same event are they likely to contradict each other?
(A) 35%
(B) 25%
(C) 20%
(D) 40%
Answer: (A)
Explanation:
They will contradict when 1 is says truth and other lies.
p(ram_truth)=3/4
p(shyam_truth)=4/5
p(ram_lies)=1-3/4= 1/4
p(shyam_lies)=1-4/5= 1/5
contradict %= [p(ram_truth) * p(shyam_lies) + p(shyam_truth) * p(ram_lies) ]*100
=[3/4 * 1/5 + 4/5 * 1/4]*100
=35%
