First we determine the probability that all the red chips are drawn, then all the blue, then all the green.
The probability that the first chip is red is 2/9, and that the second is red is 1/8. Then the probability that the third chip is blue is 3/7, that the fourth is blue is 2/6, and that the fifth is blue is 1/5. At this point, only green chips will remain.
So the probability of getting this order is 2/9 * 1/8 * 3/7 * 2/6 * 1/5 = 1/1260.
There are then six orders in which the three blocks of colors can be placed. Each order has equal probability, so the final answer is 6/1260 = 1/210.
No comments:
Post a Comment