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    Question

    A person travels at the speeds of 18kmph, 24kmph, and

    12kmph on the surface of an equilateral triangle and the ground. Find the average speed of the entire journey. (In Kmph)
    A 16.6 Correct Answer Incorrect Answer
    B 15.3 Correct Answer Incorrect Answer
    C 18.6 Correct Answer Incorrect Answer
    D 21 Correct Answer Incorrect Answer

    Solution

    Let the side of the triangle be 72 km. As we know, Average speed = total distance/total time Time to cover 72 km distance with the speed of 18 km/hr = 72/18 = 4 hrs Time to cover 72 km distance whit the speed of 24 km/hr = 72/24 = 3 hrs Time to cover 72 km distance with the speed of 12 km/hr = 72/12 = 6 hrs   Average speed = (3 x 72) / (4+ 3+6) = 216/13 = 16.6 km/hr

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