document.write( "Question 1069196: A certain concrete mixture contains 4.00% cement and 5.00% sand. \r
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\n" ); document.write( "\n" ); document.write( "How many kilograms of this mixture and how many kilograms of sand should be combined with 225 kg of cement to make a batch that is 13.0% cement and 14.0% sand? Carry out all calculations exactly and round to three significant digits final answers only. \n" ); document.write( "

Algebra.Com's Answer #684620 by josgarithmetic(39618) $\"\"$ $\"About$

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The concentrations here are shown as decimal fractions.
\n" ); document.write( "x, amount of concrete mixture to add
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document.write( "    CONCRETE MIXTURE         CEMENT            SAND          TOTAL MASS\r\n" );
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document.write( "           x                 225               y             x+225+y\r\n" );
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document.write( "    ----------------------------------------------------------------------------\r\n" );
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document.write( "                          0.04x+225           0.05x+y\r\n" );
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document.write( "CONC.s                     0.13               0.14\r\n" );
document.write( "WANTED\r\n" );
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\n" ); document.write( "\n" ); document.write( "Setup the equations for the desired concentration of each material.\r
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\n" ); document.write( "\n" ); document.write( "Solve for x and y. \n" ); document.write( "

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