<PRE><B>Question 748610</B>
The difference between the present age of the father and son is 30 means

F-S=30

which we rewrite as F=S+30



5 years ago, the son age is one seventh of the father age means

7(S-5)=F-5

which we rewrite as F=7S-30


Now we can write

S+30  =  7S-30

6S =60

S=10

and so F=S+30=10+30=40


Sons is 10 and father is 40




:)
</PRE>