23 The average number of passengers arriving at a checkout c

23. The average number of passengers arriving at a checkout counter of an international airport was 4 customers every 5-minute period. The probability that over any 10-minute Interval, exactly 6 passengers will arrive at the checkout counter is:

Solution

let X be the number of passengers arriving in a 10 minute period

X follows poisson distribution

P(X) = e^-? * ?^X/x!

P(X=6) = e^-8 * 8^6 / 6! = 0.1221

hence correct choice is (a)