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Aptitude · Q47

Probability

Competitive Exams · Aptitude · question 47

Q47

A speaks truth in 60% cases B speaks truth in 70% cases. The probability that they will way say the same thing while describing a single event, is-

A.
0.54
Answer
B.
0.56
C.
0.68
D.
0.94
E.
None of these

Answer: Option A

Solution

Answer: Option A
Solution:
Let = event that A speaks the truth
And = event that B speaks the truth
Then,

P (A and B say the same thing) = P [(A speaks the truth and B speaks the truth) or (A tells a lie and B tells a lie)]
P [   or  
P   +
P (). P () + P () . P ()