New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    The ratio of the speed of boat ‘A’ in still water,

    the speed of boat ‘B’ in still water and the speed of the current is 7:5:2, respectively. If the time taken by boat ‘A’ to travel (7D – 40) km downstream is equal to the time taken by boat ‘B’ to travel (D + 70) km upstream, then find the value of ‘D’.
    A 60.5 Correct Answer Incorrect Answer
    B 65.5 Correct Answer Incorrect Answer
    C 62.5 Correct Answer Incorrect Answer
    D 61.5 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let, the speeds of boat ‘A’ and boat ‘B’, in still water and the speed of the current be 7x km/hr, 5x km/hr and 2x km/hr, respectively. According to the question, (7D – 40)/(7x + 2x) = (D + 70)/(5x – 2x) Or, 21D – 120 = 9D + 630 Or, 12D = 750 Or, D = 62.5

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