The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member.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

• Let the members be Old Having age O + other 9 having ages x and New one having age Y
  Sum of their ages = (Y + 9 × x) and average = (Y + 9 × x)/10
  Before 4 years sum was (O + 9 x – 10 × 4) and average = (O + 9 x – 10 × 4) /10
  equating, Y + 9 x = O + 9x – 40
  Y = O – 40
  Younger is 40 years younger than Old one.
• 14 years agoHelpfull: Yes(30) No(8)
• answer : 40 years
  try it in funny way :)
  let all 10 member age is 5, 5 years
  so avrg of member in current = (5+5+5+5+5+5+5+5+5+5)/10 = 50/10
  before 4 years memners avrg age was = (1+1+1+1+1+1+1+1+1+1)/10= 10/10
  bt sum of age should be same as 50 as said in d qstn it means any of members age should be 41 years
  so sum of age will be 50 years
  so replaced member age should be of 41 years
  then how much younger is d new member = 41-1= 40
  :)
  
• 9 years agoHelpfull: Yes(11) No(0)
• 40 years younger than the old member
• 14 years agoHelpfull: Yes(4) No(4)
• if suppose a1......a10 be the age of the 10 members respectively..
  a1+a2+.....+a10=n
  avg=n/10
  after 4 yrs
  a1+4+a2+4+.......+A10+4=n+40
  avg=(n+40)/10
  so 40 remain
  younger is 40 year younger than old one
  
  
• 9 years agoHelpfull: Yes(4) No(1)
• 40 years
• 14 years agoHelpfull: Yes(3) No(8)
• answer is 40 years as reduce 10 person's age by 4...that comes out to be ..................40(10*4)
• 9 years agoHelpfull: Yes(1) No(2)
• a+b+c+d+E/5=X and a+b+c+d+F-20/5=X we get f-e=20 and hence d answer is 20
• 14 years agoHelpfull: Yes(0) No(15)
• 40 years younger
• 14 years agoHelpfull: Yes(0) No(6)
• as in four years the average should increase by 4 years.but remains the same so as average denotes value per person .so for 10 members it is 40*10=40.
• 8 years agoHelpfull: Yes(0) No(0)