Question 1198048
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One 1700-pound load of feed mixture contains 25% corn, 40% bran, and roughage. 
How many pounds of corn should be added to a load of feed mixture to make the feed 40% corn?
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Let x be the mass of the corn to add, in pounds.


Then you have this equation

    0.25*1700 + x = 0.4*(1700+x)


saying that the final mixture is 40% of corn.


From the equation

    0.25*1700 + x = 0.4*1700 + 0.4x

      x - 0.4x    = 0.4*1700 - 0.25*1700

        0.6x      =     255

           x      =     255/0.6 = 425.


<U>ANSWER</U>.  425 pounds of the corn should be added.
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Solved.