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?

21.4 km/h 20.2 km/h 19.2 km/h 19.8 km/h

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