During a journey a person travels half of the distance at a speed of 18 km/h and the remaining half of the journey at a speed of 22 km/h. What is his average speed for the entire journey?

19.8 km/h

We know ,

Average speed = \(\frac{2 × S1 × S2  }{S1 + S2}\)

According to question ,

Average speed = \(\frac{2 × 18 × 22 }{18 + 22}\)

= 19.8 km/h