. The average age of 5 member of an interview board is
the same as it was 2 years ago, because an old member
has been replaced by a new member. The difference
between the ages of old and new member is

• let AV be the average and A1,A2,A3,A4,A5 be the age of 5 members.
  Then , AV = A1+A2+A3+A4+A5 / 5 ......(1) ............ 2 years before
  
  and AV = A1+2 + A2+2 + A3+2 + A4+2 + A5' / 5 ..........(2)....2 years later
  
  from (1) and (2) , we have
  
  A5 = A5' + 8
  or A5-A5' = 8
• 9 years agoHelpfull: Yes(0) No(0)