To convert the speed from kilometers per hour (km/h) to meters per second (m/s), you can use the following conversion factor: 1 km/h = 0.27778 m/s.
Given that the boy runs 4½ km (which can be written as 4.5 km) in an hour, we can calculate his speed in m/s as follows:
Speed = Distance / Time
Speed = 4.5 km / 1 hour
Speed = 4.5 km/h * 0.27778 m/s (using the conversion factor)
Speed ≈ 1.25 m/s
Therefore, the boy's speed is approximately 1.25 meters per second.