1. **State the problem:** We have a spinner spun 100 times. The frequency of red is 35, and the ratio of black to red frequencies is 2:7. We need to find the estimated probability of landing on yellow as a decimal.
2. **Identify known values:**
- Total spins: $100$
- Red frequency: $35$
- Ratio black:red = $2:7$
3. **Find black frequency:**
Since red frequency corresponds to 7 parts, black corresponds to 2 parts.
Let the common factor be $x$.
$$\text{Black frequency} = 2x, \quad \text{Red frequency} = 7x$$
Given red frequency is 35, so:
$$7x = 35 \implies x = \frac{35}{7} = 5$$
Therefore,
$$\text{Black frequency} = 2 \times 5 = 10$$
4. **Find yellow frequency:**
Total spins = black + red + yellow
$$100 = 10 + 35 + \text{yellow}$$
$$\text{yellow} = 100 - 45 = 55$$
5. **Calculate estimated probability of yellow:**
$$P(\text{yellow}) = \frac{\text{yellow frequency}}{\text{total spins}} = \frac{55}{100} = 0.55$$
**Final answer:** The estimated probability of landing on yellow is **0.55**.
Spinner Probability 04Ad0B
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