a bag contain 6 red,4 blue,2 green and 3 yellow marbles.
if four marbles are picked at random,what is the probability that one is green,two are blue and one is red?
We can pick the 1 green marble any of C(2,1) = 2 ways.
We can pick the 2 blue ones any of C(4,2) = 6 ways.
We can pick the 1 red one any of C(6,1) = 6 ways.
The number of ways we can pick that is 2*6*6 = 72
That's the numerator of the probability.
The denominator of the probability is the number of ways we can pick
any 4 marbles out of the 6+4+2=12.
That's C(12,4) = 495 ways.
So the probabiloity is 72 successful ways out of 495 possible ways.
Answer which reduces to .
Edwin