SOLUTION: A Man's age this year is three times that of his Son. If in 15 years time the Father will be twice as old as his Son, find their present ages.

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Question 182663: A Man's age this year is three times that of his Son. If in 15 years time the Father will be twice as old as his Son, find their present ages.
Found 3 solutions by kid185, Mathtut, Cally69:
Answer by kid185(2) About Me  (Show Source):
Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!
let the age of the father and son be f and s respectively
:
highlight%28f%29=red%283s%29.......eq 1
f+15=2(s+15)...eq 2
:
take f's value of 3s from eq 1 and plug it into eq 2
:
3s+15=2s+30
:
highlight%28s=15%29age of son
:
highlight%28f%29=red%283s%29=3%2815%29=highlight%2845%29age of father

Answer by Cally69(1) About Me  (Show Source):
You can put this solution on YOUR website!
Simultaneous Equations


F = Father S=Son


F - 3S = 0 (equation 1)
F - 2S = 15 (equation 2)


F - 3S = 0
- F - 2S = 15

= -1S = -15 => -15/-1 = S = 15
Eliminate Value (F)



Son = 15 years of age



F - 3S = 0 => F - 45 = 0 = Value of (F) => 45 - 0 = 45/1 = F = 45



Father = 45 years of age


To prove it.
F - 3S = 0 = 45 - 45 = 0 (equation 1)
F - 2S = 15 = 45 - 30 = 15 (equation 2)