A man goes to Ahmedabad from Kolkata at a speed of 4km/hr and returns to Kolkata at a speed of 12km/hr, through the same route. What is his average speed (in km/hr) for the entire journey?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e., 6.
Average speed for a round trip = (2 × Speed1 × Speed2) ÷ (Speed1 + Speed2)
= (2 × 4 × 12) ÷ (4 + 12)
= (96) ÷ 16
= 6 km/hr