document.write( "Question 509429: How much sand must be added to 250 kg of a cement mixture that is 22% sand to have a mixture that is 25% sand? \n" ); document.write( "

Algebra.Com's Answer #341456 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"x\"$ = kg of cement to be added
\n" ); document.write( "given:
\n" ); document.write( " $\"+.22%2A250+=+55+\"$ kg of sand initially
\n" ); document.write( "----------
\n" ); document.write( " $\"+%28x+%2B+55%29+%2F+%28x+%2B+250%29+=+.25+\"$
\n" ); document.write( " $\"+x+%2B+55+=+.25%2A%28x+%2B+250%29+\"$
\n" ); document.write( " $\"+x+%2B+55+=+.25x+%2B+62.5+\"$
\n" ); document.write( " $\"+.75x+=+7.5+\"$
\n" ); document.write( " $\"+x+=+10+\"$
\n" ); document.write( "10 kg of sand must be added
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28x+%2B+55%29+%2F+%28x+%2B+250%29+=+.25+\"$
\n" ); document.write( " $\"+%2810+%2B+55%29+%2F+%2810+%2B+250%29+=+.25+\"$
\n" ); document.write( " $\"+65+%2F+260+=+.25+\"$
\n" ); document.write( " $\"+65+=+65+\"$
\n" ); document.write( "OK \n" ); document.write( "

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