SOLUTION: an urn contains 4 green balls 2 black balls and 6 yellow balls. Four balls are selected at random, without being replaced. Find the probability of a. drawing four balls that are

Algebra ->  Probability-and-statistics -> SOLUTION: an urn contains 4 green balls 2 black balls and 6 yellow balls. Four balls are selected at random, without being replaced. Find the probability of a. drawing four balls that are       Log On


   

Question 1170026: an urn contains 4 green balls 2 black balls and 6 yellow balls. Four balls are selected at random, without being replaced. Find the probability of
a. drawing four balls that are yellow
b. drawing a black ball a yellow ball and two green balls
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


a. drawing four balls that are yellow

In choosing 4 of the 12 balls, we need to choose (1) 0 of the 4 green; (2) 0 of the 2 black; and (3) 4 of the 6 yellow:

P%280%2C0%2C4%29+=+%28C%284%2C0%29%2AC%282%2C0%29%2AC%286%2C4%29%29%2FC%2812%2C4%29

Use a calculator if necessary....

b. drawing a black ball a yellow ball and two green balls

In choosing 4 of the 12 balls, we need to choose (1) 2 of the 4 green; (2) 1 of the 2 black; and (3) 1 of the 6 yellow:

P%282%2C1%2C1%29+=+%28C%284%2C2%29%2AC%282%2C1%29%2AC%286%2C1%29%29%2FC%2812%2C4%29

Use a calculator if necessary....