Question

    A cheetah can catch a deer running with a speed of 90

    km/h and is 80 meters ahead of it, in 16 seconds. Find the time taken by the cheetah to catch a zebra that is 125 metres ahead of it and is running with a speed which is 70% of that of the deer.
    A 10 seconds Correct Answer Incorrect Answer
    B 11 seconds Correct Answer Incorrect Answer
    C 12 seconds Correct Answer Incorrect Answer
    D 13 seconds Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Speed of the deer = 90 km/h = 90 × (5/18) = 25 m/s Distance covered by the cheetah in 16 seconds = 80 metres + distance covered by the deer in 16 seconds = 80 + 25 × 16 = 80 + 400 = 480 metres So, speed of the cheetah = 480/16 = 30 m/s Speed of the zebra = 25 × (70/100) = 17.5 m/s So, relative speed of the cheetah with respect to the zebra = 30 – 17.5 = 12.5 m/s Hence, time taken by the cheetah to catch the zebra = 125/12.5 = 10 seconds

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