SOLUTION: in 12 yrs a man will be 3 times as old as his son,the difference of their present age is 30 yrs.find their present age

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Question 739983: in 12 yrs a man will be 3 times as old as his son,the difference of their present age is 30 yrs.find their present age
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
F-S=30 OR F=30+S
F+12=3(S+12)
F+12=3S+36
30+S+12=3S+36
S-3S=36-30-12
-2S=-6
S=-6/-2
S=3 YEARS OLD NOW.
F-3=30
F=30+3
F=33 YEARS OLD NOW.
PROOF:
33+12=3(3+12)
45=3*15
45=45