Question

While calculating average age of a group of 18 students, the teacher by
mistake included 3 additional people (a peon and two teachers) .From
these 3 people, two of them are 45 years old and one is 51 years old.
This increased the average age of the entire group (i.e including the
students, the peon and the 2 teachers) by 4 years. Find out the average
age of the 18 students.​

Answer 1

Step-by-step explanation:

Let the actual average age be x years.

Total age of 3 extra people= 45+45+51 = 141 years

Actual number of students= 18

Increased number of people= 21

A.T.P

21(x+4) -141 = x.18

21x + 84 -141 = 18x

3x = 57

x= 19years.

Answer: The average age of the students is 19 years.