Two years ago the average age of a family of 8 members was 18 years. After the addition of a boy, the average age of the family remains the same today. What is the age of the baby?

• 2 years ago, avg age of 8 members is
  
  tot/8=18
  
  tot=144
  
  now everyone's age should be increased by 2
  therefore 8*2= 16
  tot=144+16== 160
  let d baby's age be x
  
  given avg age of 9 members is same [ie 18]
  160+x/9=18
  x=2
  
  Therefore the baby's age is 2
• 10 years agoHelpfull: Yes(19) No(1)
• total age(8*18=144) after 2 years total age=(144+16)=160.
  let baby's age be x,therefore (160+x)/9=18,i.e,x=2 years... age of the baby 2 years.
• 10 years agoHelpfull: Yes(0) No(0)
• (8*18)+16=160
  18*9=162
  162-160=2 ans
• 6 years agoHelpfull: Yes(0) No(0)