Question 941844: A woman is 6 times older than her child.The product of their ages 7 years ago was 180.Find their present age Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website! A woman is 6 times older than her child.The product of their ages 7 years ago was 180.Find their present age
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w = woman's age now
c = child's age now
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w = 7c
(w - 7)*(c - 7) = 180
(7c - 7)*(c - 7) = 180
Quadratic equation (in our case ) has the following solutons:
For these solutions to exist, the discriminant should not be a negative number.
First, we need to compute the discriminant : .
Discriminant d=6804 is greater than zero. That means that there are two solutions: .
Quadratic expression can be factored:
Again, the answer is: 9.89188303637179, -1.89188303637179.
Here's your graph:
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c = 9.892 years
w = 69.244 years
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It's not an integral solution, probably because the moron that wrote the problem thinks "6 times older" is the same as 6 times as old.
6 times older = 7 times as old.
1 time older = 2x, not the same age.
