Hello!
I have encountered the following question, while studying for probability course:
We have a box that includes 9 balls: 4 balls painted black, 3 balls painted white, 2 balls painted red.
We take out 4 balls out of the box, without returning.
There are 2 questions, one of them I've managed to solve, and I would like to hear if I was right or not.
The second one I can't figure the answer.
1. What is the probability that all the four balls are from the same color?
The only option is to pick the 4 balls painted black. So it's (4 4) / (9 4) which is 1/126.
2. What is the probability that every ball will be in different color?
(For example, if we pick black, then white, then red, then black).
I've been trying calculating them case by case, but I ended up with tons of cases to calculate. I'm looking for a faster way.
I've been thinking of going 1-(cases), but couldn't figure out which cases to check.
What supposed to be my state of mind while solving question no.2?
Thanks in advance!
I have encountered the following question, while studying for probability course:
We have a box that includes 9 balls: 4 balls painted black, 3 balls painted white, 2 balls painted red.
We take out 4 balls out of the box, without returning.
There are 2 questions, one of them I've managed to solve, and I would like to hear if I was right or not.
The second one I can't figure the answer.
1. What is the probability that all the four balls are from the same color?
The only option is to pick the 4 balls painted black. So it's (4 4) / (9 4) which is 1/126.
2. What is the probability that every ball will be in different color?
(For example, if we pick black, then white, then red, then black).
I've been trying calculating them case by case, but I ended up with tons of cases to calculate. I'm looking for a faster way.
I've been thinking of going 1-(cases), but couldn't figure out which cases to check.
What supposed to be my state of mind while solving question no.2?
Thanks in advance!