SOLUTION: sum of the ages of son and his father is 50 years.after 5 years father will be twice as old as his son.find their present ages. sir,i made an equation for this question: x+5=2x

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Question 1024681: sum of the ages of son and his father is 50 years.after 5 years father will be twice as old as his son.find their present ages.
sir,i made an equation for this question: x+5=2x
i don't know whether it is right or not.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = son's age now
Let +f+ = father's age now
-------------------------
(1) +s+%2B+f+=+50+
(2) +f+%2B+5+=+2%2A%28+s+%2B+5+%29+
-----------------------
It's possible to solve this using just one
variable such as +x+, but I think it's
more clear to do it this way.
------------------------
(1) +f+=+50+-+s+
Substitute (1) into (2)
(2) +50+-+s+%2B+5+=+2%2A%28+s+%2B+5+%29+
(2) +55+-+s+=+2s+%2B+10+
(2) +3s+=+45+
(2) +s+=+15+
and
(1) +f+=+50+-+s+
(1) +f+=+50+-15+
(1) +f+=+35+
-----------------
The father is 35 and
the son is 15
-----------------
check:
(2) +f+%2B+5+=+2%2A%28+s+%2B+5+%29+
(2) 35+%2B+5+=+2%2A%28+15+%2B+5+%29+
(2) +40+=+2%2A20+
(2) +40+=+40+
OK