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?

$\frac{40}{3}$ km/h 15 km/h $\frac{10}{3}$ km/h $\frac{20}{3}$ km/h

$\frac{40}{3}$ km/h

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