Question

    The ratio of the speed of the boat in upstream to that

    of in downstream is 7:10, respectively. If the speed of the current is 12 km/h, then find the speed of the boat in still water.
    A 60 km/h Correct Answer Incorrect Answer
    B 68 km/h Correct Answer Incorrect Answer
    C 55 km/h Correct Answer Incorrect Answer
    D 45 km/h Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    According to the question: Let the speed of the boat in still water = x km/h Speed of the boat downstream = (x+12) km/h Speed of the boat upstream = (x−12) km/h According to the question, (x−12):(x+12)=7:10 10(x−12)=7(x+12) 10x−120=7x+84 10x−7x=84+120 3x=204 x=68 km/h

    Practice Next

    Relevant for Exams: