Solution to puzzle 83

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 Here is the solution to puzzle 83.

Let us say Gordon's current age is x and Tony's age is y.

x+y = 112

y = 112-x

When Gordon was y years old, Tony was y - (x-y). (As the age difference will remain the same)

But now Gordon is twice as old as this age - 

x = 2(2y-x)

3x -4y = 0

4x+4y = 112*4

7x = 112*4

x = 112*4/7 = 64

y = 112 - 64 = 48

Gordon is 64 years old and Tony is 48.

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