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    Question

    Traveling at a speed of 's' km/hr, 'C' requires 22

    seconds to complete one lap around the perimeter of a circular track with a radius of 35 meters. Determine the time 'T' takes to cover a distance of 400 km, where the first half is covered at a speed of (s + 4) km/hr, and the remaining half is covered at a speed of (s – 16) km/hr.
    A 25 hrs Correct Answer Incorrect Answer
    B 18 hrs Correct Answer Incorrect Answer
    C 15 hrs Correct Answer Incorrect Answer
    D 10 hrs Correct Answer Incorrect Answer
    E 5 hrs Correct Answer Incorrect Answer

    Solution

    ATQ, Distance travelled by 'C' = 2πr = 2 × (22/7) × 35 = 220 metres Speed of 'C' = 220/22 = 10 m/sec = 10 × (18/5) = 36 km/hr Therefore, s = 36 According to the question, Time taken by 'T' to cover 1st 200 km = {200/(36 + 4)} = 5 hours Time taken by 'T' to cover rest 200 km = {200/(36 – 16)} = 10 hours Total time taken = 5 + 10 = 15 hours

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