Question 1166633
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D for David's age;

D + 12 for Carmen's age.


Five years ago their ages were  (D-5) years for David and ((D+12)-5) = (D+7) years for Carmen.


Five years ago the sum of their ages was 28 years

    (D-5) + (D+7) = 28.


Simplify and find D

    2D + 2 = 28

    2D     = 28 - 2 = 26

     D              = 26/2 = 13.


<U>ANSWER</U>.  David is 13 years old.  Carmen is 13+ 12 = 25 years old.


<U>CHECK</U>.  5 years ago they were 13-5 = 8 years  and  25-5 = 20 years old with the sum of ages  8 + 20 = 28.   ! Correct !
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Solved.


Is everything clear to you in my solution ?