SOLUTION: Jeff is Three times as old as his son. In nine years, Jeff will be twice as old as his son. How old is each now?

Question 388994: Jeff is Three times as old as his son. In nine years, Jeff will be twice as old as his son. How old is each now?
Found 3 solutions by mananth, stanbon, josmiceli:
Answer by mananth(16946)   (Show Source): You can put this solution on YOUR website!
Jeff is Three times as old as his son. In nine years, Jeff will be twice as old as his son. How old is each now?
Let son's age = x
Jeff age = 3x
..
after 9 years
son = x+9 years
Jeff = 3x+9 years
..
3x+9=2(x+9)
..
3x+9 = 2x+18
-2x
3x-2x+9 = 18
x+9=18
-9
x=18-9
x=9... Son's age
Jeff's age = 3x = 27 years
...
m.ananth@hotmail.ca

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Jeff is Three times as old as his son.
In nine years, Jeff will be twice as old as his son.
How old is each now?
---
Equations:
j = 3s
(j+9) = 2(s+9)
----
Substitute for "j":
(3s+9) = 2s+18
s = 9 (Son's age now}
---
j = 3s = 27 (Jeff's age now)
==============================
Cheers,
stan H.
=============

Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!
Let = Jeff's age now
Let = his Son's age now
= Jeff's age in 9 years
= Son's age in 9 years
-------------------------
given:
(1)
(2)
----------------
From (2):

By substitution:

and

Jeff is 27 and his Son is 9
In 9 years, Jeff will be 36 and his Son will be 18
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