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The average age of 20 boys in a class is 12 years. 5 new boys are admitted to the class whose average age is 7 years. The average age of the boys in the class becomes
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- 8.2 years
- 9.5 years
- 12.5 years
- 11 years
- 8.2 years
Correct Option: D
Given , The average age of 20 boys in a class = 12 years.
The average age of admitted to class 5 new boys = 7 years.
| New average age of class = | 20 × 12 + 5 × 7 | = | 240 + 35 |
| 25 | 25 |
| New average age of class = | 275 |
| 25 |
New average age of class = 11 years
