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?
Answer & explanation
Correct answer: option 4
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