A man goes to Chennai from Hyderabad at a speed of 56km/hr and returns to Hyderabad at speed of 72km/hr, through same route. What is his average speed (in km/hr) of the entire journey?

Correct option is D

Given:
Speed while going to Chennai = 56 km/h
Speed while returning to Hyderabad = 72 km/h
Formula Used:
​$$\text{Average Speed} = \frac{2 \times \text{Speed 1} \times \text{Speed 2}}{\text{Speed 1} + \text{Speed 2}}$$​​
where,
Speed₁ is the speed while going to Chennai,
Speed₂ is the speed while returning to Hyderabad.
Solution:
​$$\text{Average Speed} = \frac{2 \times 56 \times 72}{56 + 72} \\\ \\\text{Average Speed} = \frac{2 \times 4032}{128} = \frac{8064}{128} = 63 \, \text{km/h}$$​​
Thus, the average speed of the entire journey is 63 km/h.