an urn contains 5 red , 6 blue and 8 green balls . 4 balls are randomly selected from the urn , find the probability that the drawn ball are 1 blue and 1 red and 2 green balls ?
"sample space = no . of ways 4 balls were drawn from urn = 19 c 4 = 3876 no . ways 1 blue and 1 red and 2 green balls were drawn from bag = 6 c 1 * 5 c 1 * 8 c 2 = 840 probability = 840 / 3876 = 70 / 323 ans - a"
divide(multiply(choose(6, 1), choose(5, 1)), choose(add(add(5, 6), 8), 4))