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### Hard Puzzle Age

Hard Puzzle Age - 3 November

The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?

1. 40 yrs younger than older person.

2. 40
Each of the other 9 members will be older by 4 years,
so 4*9=36
so the new member need to be younger by 36 from the old one from 4 years ago
s0 36+4=40

4. 36 years younger than the member he was replaced with. :)

5. 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 old person is 40yrs older than young one.

In line 5 should read x+4*9 +y
and the answer would be 36 -Tarique

1. 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 old person is 40yrs older than young one.