If the mean age of 25 students is 12. If the teacher's age is also included the mean age is increased by 1. What is the age of the teacher (in years)


Given: The mean age of 25 students is 12. If the teacher's age is also included the mean age is increased by 1.

To do: To find the age of the teacher $(in\ years)$.

Solution:

Number of students$=25$

Mean age$=12$

Mean$=\frac{Sum\ of\ ages}{Number\ of\ students}$

Sum of ages$=25\times12=300$

Now, If one more person is added the mean increases by $1$.

Therefore, New mean$=13$

Sum of ages$=13\times26=338$

Teacher's age$=338-300=38$ years

 Thus, the teacher's age is $38$ years.

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Updated on: 10-Oct-2022

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