Probability and Tree Diagrams Questions and Revision | MME - Free Printable

Let me carefully analyze the image to understand what the problem is asking.

The image shows a probability tree with two stages:
- First selection: R with probability 4/9, B with probability 5/9
- Second selection: From R, we get R with probability 3/8 and B with probability 5/8; from B, we get R with probability 4/8 and B with probability 4/8

Since the user hasn't specified what exactly needs to be calculated (like probability of specific outcomes), I need to determine the most likely question based on this tree diagram. Common questions with such trees include:
- Probability of getting two reds (R then R)
- Probability of getting two blues (B then B)
- Probability of getting one red and one blue in any order
- Probability of getting at least one red
- Probability of getting exactly one red

Looking at the structure, the most basic calculation would be finding the probability of a specific path, like "R then R" or "B then B". Since the problem asks for "the final answer" and no specific question is stated, I should calculate the probability of getting two red balls (R then R), which is a standard question for such diagrams.

Let me calculate:
- P(R then R) = P(first R) × P(second R | first R) = (4/9) × (3/8) = 12/72 = 1/6

But let me double-check if there might be another common question. The tree has four endpoints:
1. R→R: (4/9) × (3/8) = 12/72
2. R→B: (4/9) × (5/8) = 20/72
3. B→R: (5/9) × (4/8) = 20/72
4. B→B: (5/9) × (4/8) = 20/72

Wait, let me verify the last one: from B, the probabilities are 4/8 for R and 4/8 for B, so B→B is (5/9) × (4/8) = 20/72.

The sum should be 1: 12+20+20+20 = 72/72 = 1, which checks out.

Since the user hasn't specified which probability to find, but the format requires a single final answer, and given that "R then R" is often the first thing asked, I'll go with that. However, let me look more carefully at the image structure.

Actually, let me zoom in to make sure I'm reading the fractions correctly.