The average age of a couple married four years ago was 25 years then. The average age of the family consisting of husband, wife and a child now is 20 years. What is the child’s present age?
Let the age of father 4 years ago be X Let the age of mother 4 years ago be Y
The average age of a couple married four years ago was 25 years then.
So, (x + Y) ÷ 2 = 25 X + Y = 25 * 2 X + Y = 50 (eqn 1)
The average age of the family consisting of husband, wife and a child now is 20 years
Age of father after 4 years is then X + 4 Age of mother after 4 years is then Y + 4 Let age of child now be Z
So, ((X + 4) + (Y+4) + Z) ÷ 3 = 20 X + 4 + Y + 4 + Z = 20 * 3 X + Y + Z + 8 = 60 X + Y + Z = 60 - 8 X + Y + Z = 52 (eqn 2)
putting (eqn 1) into (eqn 2) 50 + Z = 52 Z = 52 - 50 Z = 2
The average age of a couple married four years ago was 25 years then. The average age of the family consisting of husband, wife and a child now is 20 years. What is the child’s present age?
Let the age of father 4 years ago be X Let the age of mother 4 years ago be Y
The average age of a couple married four years ago was 25 years then.
So, (x + Y) ÷ 2 = 25 X + Y = 25 * 2 X + Y = 50 (eqn 1)
The average age of the family consisting of husband, wife and a child now is 20 years
Age of father after 4 years is then X + 4 Age of mother after 4 years is then Y + 4 Let age of child now be Z
So, ((X + 4) + (Y+4) + Z) ÷ 3 = 20 X + 4 + Y + 4 + Z = 20 * 3 X + Y + Z + 8 = 60 X + Y + Z = 60 - 8 X + Y + Z = 52 (eqn 2)
putting (eqn 1) into (eqn 2) 50 + Z = 52 Z = 52 - 50 Z = 2
Answer: 2 years
BY Riddles Repository - Answers
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