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

    Question

    A boatman rows 6 km in 8 minutes, along the stream and

    36 km in 4 hours against the stream. The speed of the stream is:
    A 26 km/hr Correct Answer Incorrect Answer
    B 4.5 km/hr Correct Answer Incorrect Answer
    C 18 km/hr Correct Answer Incorrect Answer
    D 27 km/hr Correct Answer Incorrect Answer
    E 22.5 km/hr Correct Answer Incorrect Answer

    Solution

    Rate downstream = 6/8 x 60 = 45 km/hr Rate upstream = 36/4 = 9 km/hr Speed of current = 1/2 (Rate downstream – Rate upstream) ⇒ 1/2 (45 – 9) km/hr = 18 km/hr

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