Question 1199803
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 x = the son current age;

3x = Joan current age.


In 10 years from now

    3x + 10 = 2*(x+10)

    3x + 10 = 2x + 20

    3x - 2x = 20 - 10

       x    =    10.


<U>ANSWER</U>.  The son is 10 years old.  Joan is 3*10 = 30 years old.
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Solved.