Three cities A, B and C are equidistant from each other. A motorist travels…
Three cities A, B and C are equidistant from each other. A motorist travels from A to B at 30 km/hr, from B to C at 40 km/hr and from C to A at 50 km/hr. Then the average speed is:
Answer: C. 38.3 km/hr — The three distances are equal. Let each distance be d. Total distance = 3d. Total time = d/30 + d/40 + d/50 = d(20 + 15 + 12)/600 = 47d/600. Average speed =…
- A.
39 km/hr
- B.
40 km/hr
- C.
38.3 km/hr
- D.
37.6 km/hr
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Correct answer: C
The three distances are equal. Let each distance be d.
Total distance = 3d.
Total time = d/30 + d/40 + d/50 = d(20 + 15 + 12)/600 = 47d/600.
Average speed = 3d/(47d/600) = 1800/47 ≈ 38.3 km/hr.
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