The probability of a train arriving on time and leaving on time is 0.8. the probability of the same train arriving on time is 0.84. the probability of of this train leaving on time is 0.86. given the train arrived on time, what is the probability it will leave on time?

The answer is 0.95 or equal to 95%.

To calculate this, we will use a conditional probability rule which calculates the probability of a event after another event has already occurred.
P(B║A) = P(A and B)/P(A)

P(A) = 0.84
P (A and B) = 0.8

So, P(B║A) = 0.8 / 0.84 = 0.95 = 95%.