Question

    A boat can travel 8 km more in downstream than that in

    upstream, in 8 hours while the difference between the time taken by the same boat to travel 200 km and 126 km, in still water, is 4 hours. Find the approximate time taken by the boat to travel 267 km in downstream and 173 km in upstream.
    A 24 hours Correct Answer Incorrect Answer
    B 14 hours Correct Answer Incorrect Answer
    C 34 hours Correct Answer Incorrect Answer
    D 44 hours Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the speed of boat in still water and speed of stream be 'x' km/hr and 'y' km/hr, respectively. According to question; (200/x) - (126/x) = 4 Or, (74/x) = 4 So, x = 18.5 Now, 4 x (18.5 + y) = 4 x (18.5 - y) + 8 Or, 74 + 4y = 74 - 4y + 8 Or,  8y = 8 So, y = 1 So, downstream speed of the boat = (18.5 + 1) = 19.5 km/hr And, upstream speed of the boat = (18.5 - 1) = 17.5 km/hr Required time taken = (267/19.5) + (173/17.5) ~ (14 + 10) ~ 24 hours

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