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

    Question

    A boat can cover 40 km upstream and 60 km downstream in

    13 hour. Also it can cover 50 km upstream and 72 km downstream in 16 hour. Find the speed of boat in still water.
    A 9.5 kmph Correct Answer Incorrect Answer
    B 7.5 kmph Correct Answer Incorrect Answer
    C 6 kmph Correct Answer Incorrect Answer
    D 8.5 kmph Correct Answer Incorrect Answer
    E 7 kmph Correct Answer Incorrect Answer

    Solution

    Let upstream speed = a And downstream speed = b Now, => 40/a + 60/b = 13 ------- (i) And, => 50/a + 72/b = 16 ------- (ii) Solving (i) and (ii) we get, => a = 12 and b = 5 Speed of boat in still water = (a + b)/2 = (12 + 5)/2 = 8.5 kmph

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