Question 208361:  Five years ago, John's age was half of the age he will be in 8 years.  How old is he now? 
 Answer by Theo(13342)      (Show Source): 
You can  put this solution on YOUR website! let x be john's age now. 
five years ago, john's age was x-5 
eight years from now, john's age will be x+8 
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Five years ago, John's age was half of the age he will be in 8 years. 
this means that (x-5) = (x+8)/2 
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solving for x, we get: 
2 * (x-5) = x + 8 
which becomes: 
2x - 10 = x + 8 
which becomes: 
x = 18 
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john is 18 years old now. 
5 years ago john was 13 
8 years from now john will be 26 
13 = 1/2 * 26 
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