Answer:
1/20
Explanation:
Simple probability problems are the best because the method is easily applicable to everything else!
There are 5 total marbles and 1 of each color.
So the first draw has a 1 / 5 probability of being blue.
The second draw has a 1 / 4 probability of being yellow (there are only 4 remaining marbles in the bag after you take the blue out permanently)
Then, you multiply these together, and get:
1/20!
Good luck!