Question 1140129
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    x +     y = 90000    (1)

0.05x + 0.03y = 4040     (2)


Multiply equation (2) by 20 (both sides). Keep equation (2) as is. You will get


    x  +    y = 90000    (1')

    x  + 0.6y = 80800    (2')


Now subtract equation (2') from equation (1'). You will get

         0.4y = 90000 - 80800 

         0.4y = 9200

            y = 9200/0.4 = 2300.


<U>ANSWER</U>.  Gross sale for product B was  $23000;  gross sale for product A was the rest,  90000-23000 = 67000 dollars.


<U>CHECK</U>.  0.03*23000 + 0.05*67000 = 4040 dollars.    ! Correct !
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Solved.


I used the Elimination method to solve the system of equations.