Question

The average age of 30 students and the class teacher is20 years. I f the class teacher's age is excluded; the average reduces by 1 year. What is the age of the class teacher?

Answer 1

Step-by-step explanation:

Let the age of teacher = t

Sum of the ages of 20 students = S

Given that, the average age of 20 students and the teacher is 16 years.

(S+t) /21 = 16 ———-(1)

Also given that, when the teacher is excluded then the average age is decreased by 1 year.

S/20 = 15 ———-(2)

From (2), S = 15x20 = 300

Substitute in (1),

(300+t) /21 = 16

300+t = 336

t=36

Ans: Age of the teacher is 36 years

Answer 2

50

Step-by-step explanation:

p+q/31=20

q/30=19

q=570

so p= 50

where p is age of teacher

and q is sum of ages30 students