Single correct option
A car travels from city X to city Y at a speed of 60 km/hr and returns from Y to X at a speed of 40 km/hr. Find its average speed for the entire round trip (in km/hr).
- A. 48
- B. 50
- C. 52
- D. 45
Show answer and solution
Answer: (A) 48
For equal distances covered at two speeds, average speed = 2ab/(a+b) = (2×60×40)/(60+40) = 4800/100 = 48 km/hr. Note this is the harmonic mean of the two speeds, not the simple average (which would incorrectly give 50).
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