Question 1149350
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Let B be the number of blue balls;

then the number of red balls is (B+6), and the number of green balls is (B-4).


The total is 50, i.e.


    B + (B+6) + (B-4) = 50.


Simplify and solve for B


    3B +2 = 50

    3B = 50 - 2 = 48

     B          = 48/3 = 16.


<U>ANSWER</U>.  There are 16 blue balls.
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