Question

    In a 250 metres race, 'K' beats 'M' by 50 metres, and 'M'

    beats 'L' by 20 metres. By how many metres does 'K' beat 'L'?
    A 66 m Correct Answer Incorrect Answer
    B 75 m Correct Answer Incorrect Answer
    C 25 m Correct Answer Incorrect Answer
    D 36 m Correct Answer Incorrect Answer

    Solution

    ATQ,

    Time taken by 'K' to finish = t seconds

    Then, 'M' covers = 250 - 50 = 200 metres

    So, ratio of speeds of 'K' and 'M' = 250 : 200 = 5 : 4

    Now, 'M' beats 'L' by 20 metres:

    Speed ratio of 'M' and 'L' = 250 : (250 - 20) = 250 : 230 = 25 : 23

    Combining:

    K : M : L = 5×25 : 4×25 : 4×23 = 125 : 100 : 92

    When 'K' runs 250 metres, 'L' covers = 250 × (92/125) = 184 metres

    So, 'K' beats 'L' by 250 - 184 = 66 metres

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