SOLUTION: S is 1/4 if the age of father. in 12 years he will be 2/5 of the age of father so what is their ages now? please show me the equations to solve.

Question 87499: S is 1/4 if the age of father. in 12 years he will be 2/5 of the age of father so what is their ages now?
please show me the equations to solve.
Found 2 solutions by stanbon, Earlsdon:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
S is 1/4 if the age of father. in 12 years he will be 2/5 of the age of father so what is their ages now?
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Ages NOW DATA:
Let S be x yrs. old ; Father is 4x yrs old.
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In 12 years DATA:
S will be x+12 ; Father will be 4x+12
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EQUATION:
x+12 = (2/5)(4x+12)
5x+60 = 8x+24
3x = 36
x = 12 yrs old (S's age NOW)
4x = 48 yrs old (Father's age NOW)
=============
Cheers,
Stan H.
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
Let S = age of S and F = age of father.
1) "S is 1/4 of the age of father".
2) "In 12 years (S+12) he will be 2/5 of the age of father (F+12)".
Substitute the S from eqation 1) into equation 2) and solve for F.
Simplify.
Multiply through by the LCD of 20 to clear the fractions.
Subtract 5F from both sides.
Subtract 96 from both sides.
Finally, divide both sides by 3.

So, Father's present age is 48 years.

So, S's present age is 12 years.
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