document.write( "Question 786320: a 20-lb bag of cement contains 25% cement and 75% sand. How much pure cement must be added to produce a cement mix that is 40%?\r
\n" ); document.write( "\n" ); document.write( "I can't access my e-text to look up the procedure.\r
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Algebra.Com's Answer #477863 by josgarithmetic(39620) $\"\"$ $\"About$

You can put this solution on YOUR website!
How much mixture is needed? Do you want the solution starting from 20 pounds of cement in the bag?
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\n" ); document.write( "You seem to have a MIXTURE of \"cement\" at 25% PURE CEMENT and you want to add more PURE CEMENT so that the new mixture is 40 % PURE CEMENT. HERE is how this would work:\r
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\n" ); document.write( "\n" ); document.write( " $\"highlight%28%2820%2A25%2Bw%2A100%29%2F%2820%2Bw%29=40%29\"$
\n" ); document.write( "If you are able to study this formula and understand it, then you are learning. You would next just need to solve for w.
\n" ); document.write( "The variable, w, here was assigned as the unknown amount of pure cement to add to the 20 pound cement to get your target 40% pure cement. \n" ); document.write( "

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