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

    Question

    A boat takes 12 hours longer to

    cover 378 km upstream than it does to cover the same distance downstream. The speed of the stream is 12 km/h. What is the distance the boat travels downstream in 13 hours?
    A 500 Km Correct Answer Incorrect Answer
    B 446 Km Correct Answer Incorrect Answer
    C 554 Km Correct Answer Incorrect Answer
    D 546 Km Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Let the speed of boat in still water= 'd' Kmph 378/(d-12) – 378/(d+12)=12 378 (d+12-d+12)=12(d -144) 378 (24)=12(d -144) 756= d -144 d =900 d=30 Downstream speed of boat = 30+12 = 42 Kmph Required answer = 42×13 = 546 Km

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