1. **State the problem:** We have a bag with 7 red, 5 blue, and 4 green marbles, totaling $7 + 5 + 4 = 16$ marbles.
We draw 3 marbles without replacement and want the probability that all 3 are red.
2. **Formula for probability without replacement:**
$$P(\text{all red}) = \frac{\text{number of ways to choose 3 red marbles}}{\text{number of ways to choose any 3 marbles}} = \frac{\binom{7}{3}}{\binom{16}{3}}$$
3. **Calculate combinations:**
$$\binom{7}{3} = \frac{7 \times 6 \times 5}{3 \times 2 \times 1} = 35$$
$$\binom{16}{3} = \frac{16 \times 15 \times 14}{3 \times 2 \times 1} = 560$$
4. **Calculate probability:**
$$P = \frac{35}{560}$$
5. **Simplify fraction:**
$$P = \frac{\cancel{35}}{\cancel{560}} = \frac{1}{16}$$
6. **Convert to decimal:**
$$P = 0.0625$$
7. **Round to nearest 1000th:**
$$0.0625 \approx 0.063$$
**Final answer:** The probability that all three marbles drawn are red is approximately $0.063$.
Red Marbles 2Fbee8
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