A steamer moves with a speed of 4.5 km/h in still water to a certain upstream point and comes back to the starting point in a river which flows at 1.5 km/h. The average speed of steamer for the total journey is

A 12 km\/h
B 10 km\/h
C 6 km\/h
D 4 km\/h

Correct Answer: 4 km\/h

Speed of streamer = 4.5 km/hrSpeed of water = 1.5 km/hr

Downstream speed = 4.5+1.5 = 6 km/hr

Upstream speed = 4.5 -1.5 = 3 km/hr

Average Speed = (6 X 3) / 4.5 = 4km/hr

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