Question

Average age of 30 kids is 9 years. If the teacher's age is included, the average age becomes 10 years. What is the teacher's age?

Answer 1

Answer:

30

Step-by-step explanation:

Average= sum of the ages/no. of the people

lets take sum= x

x/30=9

x=270

take teacher's age as y

since teacher is added no. of the people are 31.

270+y/31=10

270+y=310

y=310-270

y=40

Age of teacher is 40 years.