Question: A car is travelling at $48.6$ km/h. Convert this speed into m/s.
1. **State the problem:** Convert the speed from kilometers per hour (km/h) to meters per second (m/s).
2. **Formula:** To convert km/h to m/s, use the formula:
$$\text{speed in m/s} = \text{speed in km/h} \times \frac{1000}{3600}$$
This is because 1 km = 1000 m and 1 hour = 3600 seconds.
3. **Apply the formula:**
$$48.6 \times \frac{1000}{3600}$$
4. **Simplify the fraction:**
$$\frac{1000}{3600} = \frac{10}{36} = \frac{5}{18}$$
5. **Calculate:**
$$48.6 \times \frac{5}{18}$$
6. **Multiply:**
$$48.6 \times \frac{5}{18} = \frac{48.6 \times 5}{18} = \frac{243}{18}$$
7. **Simplify the fraction:**
$$\frac{243}{18} = \frac{\cancel{243}}{\cancel{18}} = 13.5$$
8. **Final answer:**
The speed in meters per second is $13.5$ m/s.