Question

    Section 4

    Ratio of speed of boat in downstream and speed of stream

    is 7:4, if speed of current is 8 km/hr, then find distance travelled (in km) upstream in 7 hours.
    A 70 km Correct Answer Incorrect Answer
    B 84 km Correct Answer Incorrect Answer
    C 60 km Correct Answer Incorrect Answer
    D 90 km Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let speed of downstream and speed of stream be 7x and 4x respectively. Speed of current => 4x = 8 => x = 2 km/hr Downstream speed = 7 × 2 = 14 km/h Speed of boat = 14 - 2 = 12 km/hr Upstream speed = 12 - 2 = 10 km/h Distance travelled upstream in 7 hr = 10 × 7 = 70 km

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