New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    A boatman rows 2 km in 5 minutes, along the stream and

    12 km in 3 hours against the stream. The speed of the stream is:
    A 10 km/hr Correct Answer Incorrect Answer
    B 20 km/hr Correct Answer Incorrect Answer
    C 14 km/hr Correct Answer Incorrect Answer
    D 12 km/hr Correct Answer Incorrect Answer
    E 6 km/hr Correct Answer Incorrect Answer

    Solution

    Rate downstream = 2/5 x 60 = 24 km/hr Rate upstream = 12/3 = 4 km/hr Speed of current = 1/2 (Rate downstream – Rate upstream) ⇒ 1/2 (24 – 4) km/hr = 10 km/hr

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