If a person travels a certain distance at a speed of 10 km/h, and returns through the same route at a speed of 20 km/h, then what will be the average speed during the whole journey?
Answer & explanation
Correct answer: option 1
We know ,
Average speed = \(\frac{2 × S1 ×S2 }{S1 + S2}\)
According to question ,
Average speed = \(\frac{2 × 10 × 20 }{10 + 20}\)
= \(\frac{400 }{30}\)
= \(\frac{40 }{3}\) km/h