Question

3. The average age of 30 students of a class is 12 yr. The
average age of a group of 5 of the students is 10 yr and
that of another group of 5 of them is 14 yr. what is the
average age of the remaining students ?

Answer 1

Answer:

Average age of 30 students in a class = 12 years

5 students = 10 years

Another 5 students = 14 years

remaining student= 30-5-5=20

let's assume average age of 20 student=x

Total age of all student=average age* total no of student

30∗12=5∗10+5∗14+20∗x

360=50+70+20x

360=120+20x

240=20x

x=12