probability question? WILL MEDAL. comment if can help

Question

anonymous · Answer

QUESTION: In a bowl of jelly beans there are 12 red, 10 black, 5 white, and 3 green. If three jelly beans are chosen one at a time. What is the probability that 3 black jelly beans will be chosen?

amistre64 · Answer

and your thoughts?

anonymous · Answer

Well im not quite sure how to figure this one out.

amistre64 · Answer

im sure, i just need to know what youve considered

amistre64 · Answer

what would be the probability of pulling 1 black bean?

redheadangel · Answer

First find the total amount of jelly beans..@amistre64 will help :)

anonymous · Answer

Theres 30 total

amistre64 · Answer

so out of 30 to start with, whats the probability that you pull a black one?

anonymous · Answer

1/30

amistre64 · Answer

10 out of 30 actually :)

amistre64 · Answer

10/30  is the probability of pulling a black bean

we have 29 left, and 9 black beans to choose from,  what is the probability of pulling the next black bean?

anonymous · Answer

oh yeah considering theres 10 black beans

anonymous · Answer

9/29?

amistre64 · Answer

|dw:1418338994694:dw|

amistre64 · Answer

yep, so if we build a tree, we see that the probability of 3 black beans pulled is just the product of their probabilities

10.9.8
--------
30.29.28