Answer:
(a) See attachment for tree diagram
(b) 24 possible outcomes
Explanation:
Given


Solving (a): A possibility tree
If urn 1 is selected, the following selection exists:
![B_1 \to [R_1, R_2, R_3]; R_1 \to [B_1, R_2, R_3]; R_2 \to [B_1, R_1, R_3]; R_3 \to [B_1, R_1, R_2]](https://img.qammunity.org/2022/formulas/mathematics/college/b6kghtj73s8bxj7b4xlslyepagk1ncgiol.png)
If urn 2 is selected, the following selection exists:
![B_2 \to [B_3, R_4, R_5]; B_3 \to [B_2, R_4, R_5]; R_4 \to [B_2, B_3, R_5]; R_5 \to [B_2, B_3, R_4]](https://img.qammunity.org/2022/formulas/mathematics/college/cdfl7t6hxwb143tuebvuiwuze2wsq4r9jt.png)
See attachment for possibility tree
Solving (b): The total number of outcome
For urn 1
There are 4 balls in urn 1

Each of the balls has 3 subsets. i.e.
![B_1 \to [R_1, R_2, R_3]; R_1 \to [B_1, R_2, R_3]; R_2 \to [B_1, R_1, R_3]; R_3 \to [B_1, R_1, R_2]](https://img.qammunity.org/2022/formulas/mathematics/college/b6kghtj73s8bxj7b4xlslyepagk1ncgiol.png)
So, the selection is:


For urn 2
There are 4 balls in urn 2

Each of the balls has 3 subsets. i.e.
![B_2 \to [B_3, R_4, R_5]; B_3 \to [B_2, R_4, R_5]; R_4 \to [B_2, B_3, R_5]; R_5 \to [B_2, B_3, R_4]](https://img.qammunity.org/2022/formulas/mathematics/college/cdfl7t6hxwb143tuebvuiwuze2wsq4r9jt.png)
So, the selection is:


Total number of outcomes is:


