Question

45. The average age of 24 students in a
class is 10 years. If teacher's age is
included to it, the average increased
by 1. Find the age of teacher.
(a) 25 years (b) 35 years
c) 30 years (d) 40 years.​

Answer 1

Step-by-step explanation:

avg=(sum of observations)/

(number of observations)

Given,

avg age of 24 students in a class is 10 yr's

avg= (sum of ages of 24 students)/(number of students)

sum of ages of 24 students is number of students *avg

sum of ages of 24 students=24*10

=240

Given,

if teacher age is included then the avg increases by 1

Let the age of the teacher is 'T'

Then

avg+1=(sum of ages of 24 students+T)/(24+1)

10+1=(240+T)/25

11=(240+T)/25

11*25=240+T

275=240+T

275-240=T

35=T

T=35 yr's

Therefore teacher's age is 35 years