SOLUTION: Laura's age is four less than three times her brother's. Seven years from now her brother will be two thirds as old as she is. How old are each of them now?
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Question 1035726: Laura's age is four less than three times her brother's. Seven years from now her brother will be two thirds as old as she is. How old are each of them now? Answer by fractalier(6550) (Show Source):
You can put this solution on YOUR website! Call Laura's and her brother's age NOW, x and y. We can then write
x = 3y - 4
Seven years from now,
(y + 7) = (2/3)(x + 7)
Now substitute the first into the second and get
y + 7 = (2/3)(3y-4 + 7)
y + 7 = (2/3)(3y + 3)
y + 7 = 2y + 2
and
y = 5 (for brother) so that
x = 3(5) - 4 = 11 years old for Laura