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Sun 25 Sep, 2005 06:27 pm
How do you set up this equation? 2 years ago, a father was 4X as old as his son. Three years from now, the father will be only 3X as old as the son. How old is each now (the father's age and the son's age.)? Please show me how to work the problem. Thank you.
Now, the age of the son is x. Two years ago, the age of the son was x-2. Three years from now, the age of the son will be x+3.
Answer
-2 Years--
F (father) = 4S (son)
+3 Years--
T (father) = 3D (son)
Now--
S + 2
F + 2
D - 3
T - 3
--------------------------------
T = 4S + 5
F = 3S - 5
D = S + 5
S = D - 5
---------------------------------
F = 3S - 5
4S = 3D - 5
S = 3/4(D) - 5/4
S = 3/4(S + 20/4) - 5/4
S = 3/4(S) + 15/4 - 5/4
4/4(S) = 3/4(S) + 10/4
1/4(S) = 5/2
S = 20/2
S = 10
F = 4S
F = 4(10)
F = 40
10 + 2 = 12
40 + 2 = 42
The son is 12 and the father is 42.
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