The average age of the members of a 10-person committee is the same as it was 4 years ago, because an old member has just been replaced by a new member.

How much younger is the new member than the old member who was replaced?

Guest May 15, 2020

#1**0 **

Let the sum of nine member (total) =x

and the age of old one=z

so its average 4 yrs before=(x+z)/10.

after 4 yrs let z be replaced by y.

so now avg=(x+4*10+y)/10

now (x+z)/10=(x+40+y)/10

so after solving it found

z=y+40.

so the older person is 40yrs older than young one

:) (sorry for the typo)

Guest May 15, 2020

edited by
Guest
May 15, 2020

edited by Guest May 15, 2020

edited by Guest May 15, 2020