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

    Question

    A motorboat in still water travels at a speed of 40

    km/hr. It goes 56 km upstream in 1 hours 45 minutes. The time taken by it to cover the same distance down the stream will be :
    A 45 minutes Correct Answer Incorrect Answer
    B 30 minutes Correct Answer Incorrect Answer
    C 1 hour 20 minutes Correct Answer Incorrect Answer
    D 1 hour Correct Answer Incorrect Answer
    E 1 hour 10 minutes Correct Answer Incorrect Answer

    Solution

    Speed of the motorboat upstream = 56/(7/4) = 32 km/hr Let the speed of the current be x km/hr ⇒ 40 – x = 32 ⇒ x = 8 km/hr Speed of motor boat downstream = 40 + 8 = 48 km/hr Time taken to cover 56 km at 48 km/hr = 56/48 = 1 hour 10 minutes

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