New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    A cheetah can catch a deer running with a speed of 54

    km/h and is 63 meters ahead of it, in 12 seconds. Find the time taken by the cheetah to catch a zebra that is 165 metres ahead of it and is running with a speed which is 80% of that of the deer.
    A 20 seconds Correct Answer Incorrect Answer
    B 22 seconds Correct Answer Incorrect Answer
    C 25 seconds Correct Answer Incorrect Answer
    D 27 seconds Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Speed of the deer = 54 km/h = 54 × (5/18) = 15 m/s Distance covered by the cheetah in 12 seconds = 63 metres + distance covered by the deer in 12 seconds = 63 + 15 × 12 = 63 + 180 = 243 metres So, speed of the cheetah = 243/12 = 20.25 m/s Speed of the zebra = 15 × (80/100) = 12 m/s So, relative speed of the cheetah with respect to the zebra = 20.25 – 12 = 8.25 m/s Hence, time taken by the cheetah to catch the zebra = 165/8.25 = 20 seconds

    Practice Next