A mother is 21 years older than her son, and in 6 years time the son will be one fifth of her age.

Where is the father?

Since by the problem, the word 'son' is specifically mentioned, it follows that we are talking about the present.

Let the respective ages of the mother and son be (s+ 252) months and s months.

Then, by the problem,

s+324 = 5(s+ 72)
or, 4s = -36
or, s = -9

Accordingly, the "present" corresponds to the period when it will be another 9 months before the "son" is born. This is a contradiction.

Consequently, the father is living "in the past".

Edited on March 7, 2008, 3:04 pm

Posted by K Sengupta on 2007-11-17 05:08:55