Problema Solution
nton is four years older than liza. the product of his age three years from now and liza's age two years ago is 90 years. find their present age
Answer provided by our tutors
Let
x = Nton's present age, x>=0
y = Liza's present age, y>=0
Nton is 4 years older than Liza:
x = y + 4
The product of his age 3 years ago from now and Liza's age 2 years ago is 90 years:
(x + 3)*(y - 2) = 90
plug x = y + 4 into last equation:
(y + 4 + 3)(y - 2) = 90
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click here to see the equation solved for y
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y = 8 years
x = 8 + 4
x = 12 years
Nton's present age is 12 years and Liza's present age is 8 years.