Question 1200692
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<pre>

Let x be the brother's age;  then the John's age is 5x, years, according to the problem.


The difference of ages is 12 years

    5x - x = 12,

or

      4x   = 12,

       x   = 12/4 = 3.


The brother is 3 years old;  John is 3*5 = 15 years old.


<U>ANSWER</U>.  John is 15 years old.
</pre>

Solved.


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This solution is so easy . . . 


You even may re-tell this solution in words - - - then you will get the MENTAL version of the solution.