The Question:

The average age of 30 students is 15 years. When the teacher's age is added, the average of the whole group increases by 1. Find the teacher's age.

Method 1 (Traditional):

  1. Total age of 30 students = 30 x 15 = 450
  2. Total members after adding teacher = 30 + 1 = 31
  3. New Average = 15 + 1 = 16
  4. Total age of 31 people = 31 x 16 = 496
  5. Teacher's age = Total Age_{(31)} - Total Age{(30)}
  6. 496 - 450 = 46 Years.

Method 2 (Booster Shortcut) ⚡:

Use the "Distributive Logic" formula:

New Member = New Average + (Previous Members x Change in Average)

  1. New Average = 16
  2. Previous Students = 30
  3. Change = +1
  4. Teacher = 16 + (30 x 1) = 46

Correct Answer: C) 46 Years

CTA:

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