A speaks truth in 60 cases and B speaks truth in 80 cases The probability that they will say the sam...........

Quantitative Aptitude ( CCS) Probability

A speaks truth in 60% cases and B speaks truth in 80% cases. The probability that they will say the same thing while describing a single event is:

Consider the following events,

A1 : A speaks truth

A2 : B speaks truth

Then, P(A1)=60/100=3/5,P(A2)=80/100=4/5

For the required event,either both of them should speak the truth or both of them should tell a lie.

Thus, the required probability is

=3/5×4/5+2/5x1/5=14/25x100=56%

Submit Error

When both of them lie, the lies could be different. So shouldn't this case not be counted?

it is 80 percent not 70 percent