SOLUTION: A father is nine times the age of his son. In 5 years he will be four times the age of his son. How old are they now?

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Question 426356: A father is nine times the age of his son. In 5 years he will be four times the age of his son. How old are they now?
Found 3 solutions by mananth, ikleyn, timofer:
Answer by mananth(16949) About Me  (Show Source):
You can put this solution on YOUR website!
Son's age x
Father's age 9x
5 years later
Son's age x +5
Father's age 9x+5
Father's age 4 times older
9x+5=4( x+5)
9x+5=4x+20
5x=20-5
5x=15
/5
x=3 Son's age
x+20=23 years Father's age

Answer by ikleyn(53427) About Me  (Show Source):
You can put this solution on YOUR website!
.
A father is nine times the age of his son. In 5 years he will be four times the age of his son.
How old are they now?
~~~~~~~~~~~~~~~~~~~~~~~~~~~


        The answer in the post by @mananth is incorrect.
        I came to bring a correct solution (including the answer). 


Son's age x

Father's age 9x

    5 years later

Son's age x +5

Father's age 9x+5


In 5 years, the father's age is four times the son age

   9x + 5 = 4(x+5)
   9x + 5 = 4x + 20
   5x = 20-5
   5x = 15
   /5

   x  =  3 years Son's age
   9x = 27 years Father's age

Solved correctly.



Answer by timofer(136) About Me  (Show Source):
You can put this solution on YOUR website!
           NOW      IN 5 YEARS
Father      9x      9x+5
Son          x      x+5

highlight_green%289x%2B5=4%28x%2B5%29%29

9x%2B5=4x%2B20
5x=15
highlight%28x=3%29 the son now
Father now, highlight%2827%29