Question 1012731
<pre>
10 years ago the father was 35, the mother was 33,
the girl was 13 and the boy was 15, their average age was

{{{(35+33+13+15)/4 = 96/4=24}}}

Now, 10 years later, the father is 45, the mother is 43, 
the girl is now a woman 23, the boy is now a man 25.

7 years ago the wife had a baby boy, who is now 7 years old.
1 year ago the wife had a baby girl, who is now 1 year old.

Now their average age is also:

{{{(45+43+23+25+7+1)/6=144/6=24}}}

The average is the same, 24, and the baby is under 2 years of age.

But there are many other solutions as well.

Edwin</pre>