Question

    The time taken by a boat to cover

    72 km downstream is 3 hours less than the boat to cover a certain distance in upstream. The downstream speed of the boat is 12 km/hr and the ratio of downstream and upstream speed of the boat is 4:3 respectively. Find the certain distance covered by the boat in upstream.
    A 68 Correct Answer Incorrect Answer
    B 78 Correct Answer Incorrect Answer
    C 81 Correct Answer Incorrect Answer
    D 61 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ,

    Downstream speed = 12km/hr. Upstream speed = 3/4 ×12 = 9km/hr. Downstream time for 72km = 72/12 = 6 hrs Let upstream distance = 'x' km. Upstream time = x/9. Given: Upstream time is 3hours more than downstream time:. (x/9) - 6 = 3. Solve = x/9 = 9 x = 81

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