Question

    The downstream speed of a boat is 8 km/hr more than its upstream speed and the ratio of the speed of the boat in still water to the speed of the stream is 7:4. Find the total time taken by boat to travel 44 km downstream and 36 km upstream?

    A 12 hrs Correct Answer Incorrect Answer
    B 10 hrs Correct Answer Incorrect Answer
    C 16 hrs Correct Answer Incorrect Answer
    D 19 hrs Correct Answer Incorrect Answer
    E 17 hrs Correct Answer Incorrect Answer

    Solution

    Let the speed of boat in still water be x km/hr and that of stream be y km/hr. ATQ, ⇒  (x + y) – (x – y) = 8 ⇒  y = 4 km/hr ⇒  x = 4 × 7/4 = 7 km/hr Required time = [44/(7+4)] + [36/(7−4)] = 16 hr

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