RE: A set S is composed of 20 multi-colored objects
March 21, 2020 at 3:27 pm
(This post was last modified: March 21, 2020 at 3:35 pm by Abaddon_ire.)
(March 21, 2020 at 2:05 pm)polymath257 Wrote:(March 18, 2020 at 5:19 am)WinterHold Wrote: I have a probability question that I need to solve:
A set S is composed of 20 multi-colored objects. 4 objects were chosen randomly from S.
What is the probability that 3 of the chosen objects be blue; knowing that there are 8 blue objects in S ?
So, I don't need hell loads of math theory. I only want steps for a solution and I'll be thankful.
Please help me.
Exactly three? Or at least three?
It's an important question.
Assuming that it is exactly three blue out of four drawn. then there are five possible results.
If there are 8 blues, then there are 12 "not blues" The number of alternate colours is irellevant.
Then the possible results are...
Blue, blue, blue, blue.
"not blue", blue, blue, blue.
Blue, "not blue", blue, blue.
Blue, blue, "not blue", blue.
Blue, blue, blue, "not blue".
From there it is mere arithmetic.
