The question is from CAT Ratio, Mixtures and Averages. When average is being affected by addition and removal, what is the value of the observation that being added to the group? CAT exam is known to test on basics rather than high funda ideas. A range of CAT questions can be asked from Ratios and Proportions, Mixtures, Alligations and Averages. Make sure you master the topics. 2IIMs CAT questions bank provides you with CAT questions that can help you gear for CAT Exam CAT 2019.
Question 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.
Difference between the age of the oldest and the newest member = 20 * 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)
The question is "Find the age of the new person."
Choice D is the correct answer.
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