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    Question

    On a certain day, 'P' leaves his

    house and reaches his school 6 minutes early when traveling at a speed of 5 km/hr. The following day, he reduces his speed by 2 km/hr and ends up reaching his school 10 minutes late. What would be the speed of 'P' if he arrives at his school exactly on time?
    A 12 km/h Correct Answer Incorrect Answer
    B 4 km/h Correct Answer Incorrect Answer
    C 8 km/h Correct Answer Incorrect Answer
    D 18 km/h Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Let time be t hours. And, distance between school and home = d So, 5 × (t – 6/60) = d --------(i) And, 3 × (t + 10/60) = d -------(ii) From (i) and (ii), we get 5 × (t – 6/60) = 3 × (t + 10/60) 5t - 1/2 = 3t + 1/2 5t – 3t = 1/2 + 1/2 2t = 1 hour, t = 1/2 hours Distance between school and home = 5 × (t – 1/10) = 5 × (4/10) = 2 km Therefore, required speed = 2/(1/2) = 4 km/h

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