Question 1152110
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<pre>

Let x be the number by Clara; 

then the number by Jeff is 3x  and the number by Yolonda is (3x+7).


The equation is  


    x + 3x + (3x + 7) = 21.


Simplify step by step and solve


    7x = 21 - 7

    7x = 14

     x = 14/7 = 2.


<U>ANSWER</U>.  Clara has 2 baseball cards.
</pre>

Solved.


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Never even try to solve this simple problem (and other similar problems) in a way as @josgarithmetic teaches you.


His way is the way to &nbsp;&nbsp;N O W H E R E</U>.


The problem is &nbsp;<U>extremely simple</U>, &nbsp;&nbsp;<U>and the solution method/methods should be adequately simple</U>.