Question

    A boatman rows 9 km in 12 minutes, along the stream and

    45 km in 3 hours against the stream. The speed of the stream is:
    A 26 km/hr Correct Answer Incorrect Answer
    B 15 km/hr Correct Answer Incorrect Answer
    C 30 km/hr Correct Answer Incorrect Answer
    D 7.5 km/hr Correct Answer Incorrect Answer
    E 22.5 km/hr Correct Answer Incorrect Answer

    Solution

    Rate downstream = 9/12 x 60 = 45 km/hr Rate upstream = 45/3 = 15 km/hr Speed of current = 1/2 (Rate downstream – Rate upstream) ⇒ 1/2 (45 – 15) km/hr = 15 km/hr

    Practice Next