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Averages Smart Math

[Smart Math] Averages Problem 7

Here’s and example of a SMART MATH problem for AVERAGES.

Averages

Problem

The average age of 25 students of a class is 10 years. When a new student is admitted, the average age becomes 10.1 years. What is the age of the new student?

  1. 10.1 years
  2. 10.6 years
  3. 11.6 years
  4. 12.0 years
  5. 12.6 years

The Usual Method

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Original total age of the class = 25 x 10 = 250 years

New total age of the class = 26 x 10.1 = 262.6 years

Difference in total ages = 250 – 262.6 = 12.6 years

Hence age of the new student = 12.6 years

(Ans: 5)

Estimated Time to arrive at the answer = 45 seconds.

Using Technique

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Average increases by 0.1 years for 25 + 1 = 26 students, so total increase = 2.6 years. Thus age of new student = 2.6 + original average age of the 25 students = 2.6 + 10 = 12.6 years.

(Ans: 5)

Estimated Time to arrive at the answer = 10 seconds.
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