Answer: Ok, so the tree would start with the ten marbles going to 1 of the reds, 1 of the black , and get till you used up all the black, then do 2/10 and 8/10 to 12 and repeat the 1 part step, and then do 4/12 and 8/12 and add it all up and place the probability out of 22.
Explanation: