CAT Practice : Averages, Ratios, Mixtures



    Q.38: A group of 20 people has the oldest person with 90 years of age. The average of the group is reduced by 4, if the oldest person is reduced by someone new, Find the age of the new person.
    1. 80 years
    2. 60 years
    3. 30 years
    4. 10 years


  • Correct Answer
    Choice D. 10 years

Detailed Solution

Difference between the age of the oldest and the newest member = 20 X 4 (because by this number the sum of ages of all the persons in the group has reduced) = 80 years
So, age of the new person = 90 – 80 = 10 years (One should be able to think like this directly and not solve such questions via the ‘x’ method as it is time consuming)

Correct Answer: 10 years

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