A man covered a certain distance in 3 parts with average speeds of 30 km/h, 60 km/h, and 90 km/h. What is his average speed over the entire journey, assuming equal distances?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 49.09 km/h.
Let each distance = D km
Time = D/30 + D/60 + D/90 = 11D/180 hours
Total distance = 3D km
Average speed = (3D) ÷ (11D/180) = 3 × 180/11 = 540/11 ≈ 49.09 km/h