Question 1089235: Three years ago the average age of a family of 5 members is 27 years. On the addition of a child to the family, the average age of the family is still 27 years. Find the present age of the child.
Found 2 solutions by ankor@dixie-net.com, ikleyn:
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Three years ago the average age of a family of 5 members is 27 years.
On the addition of a child to the family, the average age of the family is still 27 years.
Find the present age of the child.
:
let t = total of their ages 3 yrs ago
t = 5*27
t = 135
In 3 yrs, five people would add 15 yrs to the total; 150
:
let c = age of the child
we now have 6 people in the family
 = 27
150 + c = 27 * 6
150 + c = 162
c = 162 - 150
c = 12 yrs is the age of the child
Answer by ikleyn(52928)  (Show Source):
You can put this solution on YOUR website! .
OK.
All calculations by the other tutor are correct.
So, the answer 12 years is mathematically and formally correct.
Thus the child is 12 years old.
But then the problem formulation loses its sense, because the child, the 6-th member of the family, just was present three years ago.
What is the conclusion from this story ? ?? ???
The conclusion is that the problem is EITHER a) self-contradictory, OR b) nonsense, OR c) is incorrectly formulated.
You can choose between these three options which you like most of all.
|
|
|
