the U.S department of transportation reported that 80.5% of the airline flight arrive on time. Find the probability that among 12 randomly selected flight, exactly 10 arrive on time Solution Binomial Distribution PMF of B.D is = f ( k ) = ( n k ) p^k * ( 1- p) ^ n-k Where k = number of successes in trials n = is the number of independent trials p = probability of success on each trial P( X = 10 ) = ( 12 10 ) * ( 0.805^10) * ( 1 - 0.805 )^2 = 0.2868.