the avg of 8 men is increased by 2 years when one of them whose age is 24 is replaced by freshman what is his age?

let avg =x.
so sum is 8x
sum replaced 8(x+2)-24+y

8(x+2) = 8x-24+y

8x+16 = 8x-24+y
40 = y

It doesn't matter what the average age is. Replacing a 24-year-old by a 40-year-old adds 16 years to the total ages, raising the average by 2.