Question

Laim tells his son that i was your present age when you were born
If Laim is 36 now how old was his son five years ago.

Answer 1

Let, present age of Laim be x years and present age of his son be y years.
As per first statement,
Y years back,
Laims age is 'y'. (present age of his son)
$\therefore x-y=y\cdots \left(1\right)$
Given, x = 36
$\Rightarrow 36-y=y\Rightarrow y=18years$
$\therefore$ Age of his son 5 years back
= 18 - 5
= 13 years