Question

the average age of 13 boys and the principal is 10 years. when the principle are is excluded, the average age decreases by 2 years. what is the age of the principle.​

Answer 1

Answer:

The age of principal is 36yrs.

The average age of 13 boys and the principal is 10 yrs.

Total age 13 boys and principle = (13+1) *10

when teacher age excluded = 13*(10-2)

The age of teacher

= 14*10 - 13*8

=140-104

=36 yrs

Answer 2

Answer:

let the age of Principal = x

sum of age of 13 students = y

x+y = 14*10 eq 1

when Principal's age excluded

y-x = 13*8

y = 104+x eq 2

by putting it in eq 1

x+104+x = 140

2x = 140-104

2x = 36

x = 18

So, the age of Principal is 18 yrs.