Answer:
2/3
Step-by-step explanation:
To find the probability, you first have to add up the total number of marbles in the bag.
3+4+9+5=21
Next you find the probability of getting a yellow:
9/21
Then you find the probability of getting a green:
5/21
And since the problem says "yellow or green" we will add the two together
9/21 + 5/21 = 14/21 = 2/3
