1.

The average age of 12 boys is 10 years. Out of these the average age of 11 boys is 9 years. Find the age of the 12th boy?1. 25 years2. 33 years3. 21 years4. 24 years

Answer» Correct Answer - Option 3 : 21 years

Given:

Average age of 12 boys = 10 years

Average age of 11 boys = 9 years

Formula used:

Sum of ages = Average age × Number of persons

Calculation:

Total age of 12 boys = 10 × 12

⇒ 120 years

Total age of 11 boys = 9 × 11

⇒ 99 years

Age of 12th boy = (120 – 99) years

⇒ 21 years

∴ The age of 12th boy is 21 years



Discussion

No Comment Found

Related InterviewSolutions