Question

the average age of 25boys in a class decreases by 6 months when a new boy takes the place of a 20 years old boy find the age of new boy​

Answer 1

Answer:

6 months = 0.5 years

let the initial average be “i”

let new boys age be x

(25i-20+x)/25 = i- 0.5

25i-20+x = 25i-12.5

-20+x=-12.5

x= 7.5

the new bouy is 7 years and 6 months old

Answer 2

Answer:

The age of new boy is 7.5 years.