SOLUTION: The sum of ages of father and son is 36. If both live until the son becomes as old as his father is now, the sum of their ages becomes 84. Find their present ages.

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Question 855484: The sum of ages of father and son is 36. If both live until the son becomes as old as his father is now, the sum of their ages becomes 84. Find their present ages.
Found 2 solutions by ramkikk66, josmiceli:
Answer by ramkikk66(644) About Me  (Show Source):
You can put this solution on YOUR website!
The sum of ages of father and son is 36. If both live until the son becomes as old as his father is now, the sum of their ages becomes 84. Find their present ages.
Ans:
Let the son be x years old presently.
Father's current age = 36 - x
Difference between their ages = 36 - x - x = 36 - 2*x
So it will take the son another (36 - 2*x) years to become as old as the father
is today.
At that time, son's age will be 36 - x (which is the father's present age)
At that time, father's age will be 36 - x + 36 - 2*x = 72 - 3*x

So the sum of their ages will be 36 - x + 72 - 3*x = 108 - 4*x which is given 
to be 84.
So, 108 - 4*x = 84. i.e. 4*x = 24 or x = 6.
Son is highlight%286%29 years old, and father is highlight%2830%29 years old.
Check: For the son to become 30 years old it will take another 24 years. Father
will be 30+24 = 54 years old then. Sum of their ages will be 30 + 54 = 84.
Correct!

Hope this helps :)


Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = father's age now
Let +b+ = Son's age now
-------------------------
(1) +a+%2B+b+=+36+
----------------------
Subtract +2b+ from both sides
(1) +a+-+b+=+36+-+2b+
and
(1) +a+=+36+-+b+
When the Son's age is +36+-+b+ ( father's age now )
the difference in their ages will still be the same
( it never changes ), so
+36+-+b+%2B+%28+36+-+b+%2B+%28+36+-+2b+%29+%29++=+84+
+36+-+b+%2B+36+-+b+%2B+36+-+2b+=+84+
+3%2A36+-+4b+=+84+
+108+-+4b+=+84+
+4b+=+108+-+84+
+4b+=+24+
+b+=+6+
and
(1) +a+=+36+-+b+
(1) +a+=+30+
The father is 30
The son is 6
---------------
check:
In 24 years, the son will be 30
In 24 years, the father will be 54
+30+%2B+54+=+84+
OK