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.
67.50kmh -
D.
75.00kmh
Correct Answer: Option C
Explanation
Average speed from P to Q = 90kmh
Average speed from O to P = 45km/h
Average for the entire journey = 90 + 45
(frac{135}{2}) = 67.50 km/h