Question

3. The average age of 25 students is 16 years. Find
the average age, if a teacher aged 42 years is
included.
(1) 16 years
(2) 20 years
(3) 18 years
(4) 19 years
(5) None of these​

Answer 1

Answer:

Average age of 25 students = 16 years

Total age of 25 students 16 × 25 = 400 years

Average age of 25 students and teacher = 17 years

Total age of 25 students and teacher 17 × 26 = 442 yrs.

Age of teacher = 442 - 400 =42 years.

Answer 2

Answer:

the new average of students and teacher is 17 years

Option D

Step-by-step explanation:

Let the sum of ages of 25 students be x

total number of students= 25

average = 16

$\frac{x}{25} = 16$

$x = 25 \times 16$

$x = 400$

so, the sum of ages of students is 400

according to question:

the age of teacher is 42 and it should be included in the average

then,

sum of ages of the students and teacher= 400 + 42

= 442

total no. of students+ teacher = 25 + 1

= 26

average = 442/26

= 17 years

New average of students and teacher is 17 years

Hope it will helps you....