Question

A man rows a boat 27 kms in 6 hours downstream and returns upstream in 18 hours. The speed of the stream (in km per hour) is:

A 3 km/hr Correct Answer Incorrect Answer
B 2.25 km/hr Correct Answer Incorrect Answer
C 4 km/hr Correct Answer Incorrect Answer
D 4.5 km/hr Correct Answer Incorrect Answer
E 1.5 km/hr Correct Answer Incorrect Answer

Solution

Rate downstream = 27/6 = 4.5 km/hr Rate upstream = 27/18 = 1.5 km/hr Now, speed of the stream = (rate downstream – rate upstream)/2 ⇒ (4.5 – 1.5)/2 = 1.5 km/hr

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