the average age of the family of 5 members is 20years.if the age of the youngest member be 10 years then what was the average age of the family at the time of the birth of youngest member

• Average age of 5 Persons is 20 yrs.
  Therefore, Age of 1 persons is 20*5
  
• 9 years agoHelpfull: Yes(0) No(0)
• Average age of 5 Persons is 20 yrs.
  Therefore, Age of 1 persons is 20*5
  = 100
  Age of youngest member is 10 yrs.
  
  Therefore, At his birth 4x= 100-10
  4x= 90
  x=22.5 yrs.
  Average Age is 22.5 yrs.
• 9 years agoHelpfull: Yes(0) No(1)
• (4x+10) / 5 = 20
  therefore
  4x + 10 = 100
  -> 4x = 90
  
  now
  4x / 4 = ?
  therefore answer is 90/4 = 22.5
• 9 years agoHelpfull: Yes(0) No(1)
• Total age of the five members=5*20=100 years
  age of the youngest person=10 years
  Total age of the remaining 4 members=90 years
  Hence at the time of the birth of youngest person ,avg age of the family= [90-(4*10)]/4 = 12.5 years.
  
  
• 8 years agoHelpfull: Yes(0) No(0)