Question

    Traveling from point 'I' to point 'J' takes 9 hours less

    at a speed of 72 km/h compared to traveling at 36 km/h. If 70% of the distance is traveled at 63 km/h and the rest at 28 km/h, calculate the total time taken.
    A 13.2h Correct Answer Incorrect Answer
    B 14.1h Correct Answer Incorrect Answer
    C 20 h Correct Answer Incorrect Answer
    D 10.5h Correct Answer Incorrect Answer

    Solution

    Let the distance between points 'A' and 'B' = d km Then, according to the question, (d/36) - (d/72) = 9 Or {(2d - d)/72} = 9 Or d/72 = 9 So, d = 648 And so, 70% of the distance from 'A' and to 'B' = 648 X 0.7 = 453.6 km Remaining distance = 648 – 453.6 = 194.4 km So, time taken = (453.6 ÷ 63) + (194.6 ÷ 28) = 7.2 + 6.9 = 14.1 hours

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