SOLUTION: Mary is now four times as old as her daughter. Four years ago,the product of their ages was 40. Find their present ages.

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Question 1154081: Mary is now four times as old as her daughter. Four years ago,the product of their ages was 40. Find their present ages.
Answer by mananth(16946) About Me  (Show Source):
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Mary is now four times as old as her daughter. Four years ago,the product of their ages was 40. Find their present ages.
If daughter is x
Mother's age = 4x
4 years ago
daughter's age = x-4
Mother's age = 4x-4
Product of ages (x-4)((4x-4)
(x-4)((4x-4)=40
expand
4x^2-4x-16x+16 =40
4x^2-20x-24=0
x^2-5x-6=0
x^2-6x+x-6=0
x(x-6)+1(x-6)=0
(x-6)(x+1)=0
x=6 or -1
age cannot be negative
x=6
continue