Probability Tree B92Ce7
1. **State the problem:** Tina has two bags, A and B, with red and blue counters. We want to complete the probability tree diagram showing the probabilities of drawing red or blue counters from each bag.
2. **Given probabilities:**
- Bag A: $P(\text{Red})=\frac{5}{8}$, $P(\text{Blue})=\frac{3}{8}$
- Bag B: $P(\text{Red})=\frac{4}{9}$, $P(\text{Blue})=\frac{5}{9}$
3. **Probability tree structure:**
- First split: Bag A's outcomes (Red or Blue)
- Second split: For each Bag A outcome, Bag B's outcomes (Red or Blue)
4. **Calculate joint probabilities:**
- $P(\text{Red from A and Red from B}) = P(\text{Red from A}) \times P(\text{Red from B}) = \frac{5}{8} \times \frac{4}{9} = \frac{20}{72} = \frac{5}{18}$
- $P(\text{Red from A and Blue from B}) = \frac{5}{8} \times \frac{5}{9} = \frac{25}{72}$
- $P(\text{Blue from A and Red from B}) = \frac{3}{8} \times \frac{4}{9} = \frac{12}{72} = \frac{1}{6}$
- $P(\text{Blue from A and Blue from B}) = \frac{3}{8} \times \frac{5}{9} = \frac{15}{72} = \frac{5}{24}$
5. **Interpretation:** Each branch in the tree diagram is labeled with these probabilities. The first branches from Bag A are $\frac{5}{8}$ (Red) and $\frac{3}{8}$ (Blue). From each of these, branches split to Bag B's Red ($\frac{4}{9}$) and Blue ($\frac{5}{9}$) with the joint probabilities calculated above.
6. **Summary:** The completed tree diagram shows:
- Bag A Red branch: $\frac{5}{8}$
- Bag B Red: $\frac{5}{18}$
- Bag B Blue: $\frac{25}{72}$
- Bag A Blue branch: $\frac{3}{8}$
- Bag B Red: $\frac{1}{6}$
- Bag B Blue: $\frac{5}{24}$
This completes the probability tree with all probabilities labeled clearly.