Search This Blog

Loading...

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The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member.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

For Solution : Click Here

10 comments:

  1. 40 yrs younger than older person.

    ReplyDelete
  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

    ReplyDelete
  3. 36 years younger than the member he was replaced with. :)

    ReplyDelete
  4. 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.

    ReplyDelete
  5. Admin's solution is erroneous.
    In line 5 should read x+4*9 +y
    and the answer would be 36 -Tarique

    ReplyDelete
    Replies
    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.

      Delete