The average age of a father,mother and son was 42 years when the son got married.One year after marriage a baby was to the son and his wife.Five years later the average age of the family was caluculated to be 36 years.what was the age of the daughter-in-law at the time of marriage?

1)26years 2)25years 3)27years 4)23years 5)22years

• 2) 25 years
  
  Let the present age of father=F, mother=M, son=S, Daughter-in-law=D, then
  Total age at the time of marriage of son =3*42 + D = (126+D) years
  Total age at the birth of grandson= (126+D)+ 4 = D+130 years
  Total age after 5 years of all 5 persons = (D+130)+25 = D+155 = 5*36 years
  => D = 180 - 155 = 25 years
• 7 years agoHelpfull: Yes(5) No(0)
• a+b+c=126
  (a+6)+(b+6)+(c+6)+(d+6)+5=180
  a+b+c+d=151
  d=151-126=25 year
• 6 years agoHelpfull: Yes(2) No(0)