Question

The average age in a class of 15 boys and one
teacher is 15 years. If the teacher’s age is excluded,
the average age of class reduces by 1 year, then the
teacher's age is
(1) 28 years (2) 30 years
(3) 32 years (4) 34 years

Answer 1

15 boys and 1 teacher ....
total people= 15+1=16
now
sum of ages of 16 people = 16*15=240
now teacher excluded so .....
no. of people will be 16-1 = 15
new AV. is 14 yr
so sum of ages of 15 people is =15*14
= 210
now for finding teacher's age we have to minus students AV. age from all
= 240-210
30.....…....
so teacher's age is 30 yrs.....
option no. 2....

Answer 2

Answer:30 years

Step-by-step explanation:

Sumo of ages of students and teachers/16=15 years

Therefore , sumof ages of students and teachers= 15×16= 240

Also,

Sum of ages of students /15=14

Therefore, sum of ages of students =14×15=210

Now,

Age of teacher =240-210=30 years