A train moves from P to Q at an average speed of 90km/h and immediately returns from Q to P through the same route at an average speed of 45km/h. Find the average speed for the entire journey

  • A 55.00km/h
  • B 60.00km/h
  • C 67.50km\h
  • D 75.00km\h
jamb 1987mathematics

The correct answer is C. 67.50km\h

Average speed from P to Q = 90km\h

Average speed from O to P = 45km/h

Average for the entire journey = 90 + 45

\(\frac{135}{2}\) = 67.50 km/h

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