A jar contains only red, yellow, and orange marbles.
A jar contains only red, yellow, and orange marbles. If there are 3 red, 3 yellow, and 4 orange marbles, and 3 marbles are chosen from the jar at random without replacing any of them, what is the probability that 2 yellow, 1 red, and no orange marbles will be chosen?
Answer/Solution
2/45
Steps/Work
I started by finding the 2 probabilities, without calculation, like this:
P(YYR)
P(YRY)
P(RYY)
I calculated the first one and ended in 1/22. I looked at the answer choices at this point and saw answer D: 3/22.
This helped me realise that for the 3 possible orderings the probabbility is the same. So, it should be (1/45)*(2), which indeed is 2/45.
C
P(YYR)
P(YRY)
P(RYY)
I calculated the first one and ended in 1/22. I looked at the answer choices at this point and saw answer D: 3/22.
This helped me realise that for the 3 possible orderings the probabbility is the same. So, it should be (1/45)*(2), which indeed is 2/45.
C