document.write( "Question 536192: How much soli containg 45% sand do you need to add to 1 ft^3 of soil containing 15% sand in order to make a soil containing 35% sand? \n" ); document.write( "

Algebra.Com's Answer #352182 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+x+\"$ = ft3 of 45% soil
\n" ); document.write( " $\"+.45x+\"$ = ft3 of sand in 45% soil
\n" ); document.write( "given:
\n" ); document.write( " $\"+.15%2A1+\"$ = ft3 of sand in 1 ft3 of 15% soil
\n" ); document.write( "---------------
\n" ); document.write( "In words:
\n" ); document.write( "( final cubic ft of sand ) / ( final cubic ft of soil ) = 35%
\n" ); document.write( " $\"+%28+.45x+%2B+.15+%29+%2F+%28+x+%2B+1+%29+=+.35+\"$
\n" ); document.write( " $\"+.45x+%2B+.15+=+.35%2A%28+x+%2B+1+%29+\"$
\n" ); document.write( " $\"+.45x+%2B+.15+=+.35x+%2B+.35+\"$
\n" ); document.write( " $\"+.1x+=+.2+\"$
\n" ); document.write( " $\"+x+=+2+\"$
\n" ); document.write( "2 ft3 of soil with 45% sand is needed
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+.45%2A2+%2B+.15+%29+%2F+%28+2+%2B+1+%29+=+.35+\"$
\n" ); document.write( " $\"+%28+.9+%2B+.15+%29+%2F+3+=+.35+\"$
\n" ); document.write( " $\"+1.05+%2F+3+=+.35+\"$
\n" ); document.write( " $\"+1.05+=+1.05+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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