document.write( "Question 892804: A certain concrete mixture contains 5% cement and 8% sand. How many pounds of this mixture and how many pounds of sand should be combined with 255 pounds of cement to make a batch that is 12% cement and 15% sand? Set-up is my issue \n" ); document.write( "

Algebra.Com's Answer #540844 by josgarithmetic(39618) $\"\"$ $\"About$

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255 pounds of cement;
\n" ); document.write( "x pounds of the available mixture;
\n" ); document.write( "s pounds of sand;
\n" ); document.write( "Resulting Mix must be 12% cement and 15% sand.\r
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\n" ); document.write( "\n" ); document.write( "You not yet know exactly the quantity of the resulting mix, but you know it will be 255+x+s pounds.\r
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\n" ); document.write( "\n" ); document.write( "Account for Cement Result:
\n" ); document.write( " $\"%28255%2B%280.05%29x%29%2F%28255%2Bx%2Bs%29=0.12\"$ \r
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\n" ); document.write( "\n" ); document.write( "Account for Sand Result:
\n" ); document.write( " $\"%28%280.08%29x%2Bs%29%2F%28255%2Bx%2Bs%29=0.15\"$ \r
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\n" ); document.write( "\n" ); document.write( "Each of those accounting equations is written for decimal fractions instead of using percents. The equations appear as rational form but working through them to simplify shows each is a linear equation in x and s. \n" ); document.write( "

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