Question

In a class, the average age of 30 students is 9 years. If the age of their teacher is included, it becomes 10 years. The age of the teacher (in years)is ( A ) 40 ( B ) 31 ( C ) 35 ( D ) 27

Answer 1

Answer:

total students=30*9

=270

total students and teachers=31*10

=410

the age of teachers=410-270=40

Answer 2

Answer:

40 years

Step-by-step explanation:

The average age of 30 students=9 years

The total age of 30 students= 30×9=270 years

The total age of 30 students +1 teacher =31×10=310 years

So Teacher's age = (total students+teacher's age)-(total student's age)

Teacher's age= 310-270=40 years