SOLUTION: A is thrice as old as his son. In ten years, the product of their ages will be 800.How old are they now ?

Question 678811: A is thrice as old as his son. In ten years, the product of their ages will be 800.How old are they now ?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A is thrice as old as his son.
a = 3s
:
In ten years, the product of their ages will be 800.
(a+10)(s+10) = 800
Foil
as + 10a + 10s + 100 = 800
as + 10a + 10s - 700 = 0
Replace a with 3s
3s*s + 10(3s) + 10s - 700 = 0
3s^2 + 30s + 10s - 700 = 0
A quadratic equation
3s^2 + 40s - 700 = 0
Factors to
(3s+70)(s-10) = 0
The positive solution
s = 10 yrs is the son's age
:
You can find A's age. Check solution in the statement:
"In ten years, the product of their ages will be 800."

How old are they now ?
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