1. **State the problem:** A bike travels 90 km in 3 hours. We need to find its speed. 2. **Formula used:** Speed is calculated by the formula: $$\text{Speed} = \frac{\text{Distance}}{\text{Time}}$$ 3. **Apply the values:** $$\text{Speed} = \frac{90}{3}$$ 4. **Calculate:** $$\text{Speed} = 30$$ 5. **Interpretation:** The bike travels at a speed of 30 km/h. This means the bike covers 30 kilometers every hour on average.