document.write( "Question 642363: British sterling silver is a copper-silver alloy that is 7.5% copper by weight. How many grams of pure copper and how many grams of British sterling silver should be used to prepare 240 grams of a copper-silver alloy that is 16% copper by weight? \n" ); document.write( "

Algebra.Com's Answer #404087 by josmiceli(19441) $\"\"$ $\"About$

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Let grams of pure copper needed = $\"+c+\"$
\n" ); document.write( "Let grams of British sterling silver needed = $\"+s+\"$
\n" ); document.write( " $\"+.075s+\"$ = grams of copper in British sterling silver needed
\n" ); document.write( "--------------------
\n" ); document.write( "(1) $\"+c+%2B+.075s+=+.16%2A240+\"$
\n" ); document.write( "(2) $\"+.925s+=+.84%2A240+\"$
\n" ); document.write( "-------------------
\n" ); document.write( "(2) $\"+.925s+=+201.6+\"$
\n" ); document.write( "(2) $\"+s+=+201.6+%2F+.925+\"$
\n" ); document.write( "(2) $\"+s+=+217.95+\"$
\n" ); document.write( "Substitute this into (1)
\n" ); document.write( "(1) $\"+c+%2B+.075%2A217.95+=+.16%2A240+\"$
\n" ); document.write( "(1) $\"+c+%2B+16.35+=+38.4+\"$
\n" ); document.write( "(1) $\"+c+=+22.05+\"$
\n" ); document.write( "22.05 grams of pure copper are needed
\n" ); document.write( "217.95 grams of British sterling silver are needed
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+c+%2B+.075s+=+.16%2A240+\"$
\n" ); document.write( "(1) $\"+22.05+%2B+.075%2A217.95+=+.16%2A240+\"$
\n" ); document.write( "(1) $\"+22.05+%2B+16.35+=+38.4+\"$
\n" ); document.write( "(1) $\"+38.4+=+38.4+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );