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NTPC Graduate Tier 1 2016 Shift 2 📅 02 Apr, 2016

If P travelled the first half of a journey at 40 km/hr and the remaining distance at 50 km/hr, what is the average speed of his travel?

A
44.44 km/hr
B
53.33 km/hr
C
45 km/hr
D
60 km/hr
Result Summary
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APEDIA

NTPC Graduate Tier 1
2016 • 02 Apr, 2016 • Shift 2
If P travelled the first half of a journey at 40 km/hr and the remaining distance at 50 km/hr, what is the average speed of his travel?
Correct Answer
44.44 km/hr
Kinematic Principle: Average speed is not a simple arithmetic mean of the two speeds. Because different speeds are maintained over equal segments of distance, t......
💡 Analysis & Explanation
Kinematic Principle ▼
Average speed is not a simple arithmetic mean of the two speeds. Because different speeds are maintained over equal segments of distance, the time spent traveling at the slower speed is longer.
Formula Application ▼
For two equal halves of a journey traversed at speed 'x' and speed 'y', the harmonic mean formula for average speed applies: (2xy) / (x + y).
Variable Substitution ▼
Let x = 40 km/hr and y = 50 km/hr.
Calculation Steps ▼
Average Speed = (2 * 40 * 50) / (40 + 50) = 4000 / 90.
Final Output ▼
4000 divided by 90 equals 44.444...
Conclusion ▼
The average speed for the entire journey is precisely 44.44 km/hr.