document.write( "Question 739702: A candy company wants to produce 20 kilograms of a special 45% fat content chocolate. To obtain this, a 50% fat content chocolate is combined with a 30% fat content chocolate. How many kilograms of the 50% fat content and the 30% fat content are used to make the required 20 kilograms? \n" ); document.write( "

Algebra.Com's Answer #451263 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+a+\"$ = kg of 50% fat chocolate needed
\n" ); document.write( "Let $\"+b+\"$ = kg of 30% fat chocolate needed
\n" ); document.write( "------------------
\n" ); document.write( "(1) $\"+a+%2B+b+=+20+\"$ kg
\n" ); document.write( "(2) $\"+%28+.5a+%2B+.3b+%29+%2F+20+=+.45+\"$
\n" ); document.write( "---------------------------
\n" ); document.write( "(2) $\"+.5a+%2B+.3b+=+.45%2A20+\"$
\n" ); document.write( "(2) $\"+.5a+%2B+.3b+=+9+\"$
\n" ); document.write( "(2) $\"+5a+%2B+3b+=+90+\"$
\n" ); document.write( "Multiply both sides of (1) by $\"+3+\"$
\n" ); document.write( "and subtract (1) from (2)
\n" ); document.write( "(2) $\"+5a+%2B+3b+=+90+\"$
\n" ); document.write( "(1) $\"+-3a+-+3b+=+-60+\"$
\n" ); document.write( " $\"+2a+=+30+\"$
\n" ); document.write( " $\"+a+=+15+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+a+%2B+b+=+20+\"$
\n" ); document.write( "(1) $\"+b+=+5+\"$
\n" ); document.write( "15 kg of 50% fat chocolate are needed
\n" ); document.write( "5 kg of 30% fat chocolate are needed
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+%28+.5a+%2B+.3b+%29+%2F+20+=+.45+\"$
\n" ); document.write( "(2) $\"+%28+.5%2A15+%2B+.3%2A5+%29+%2F+20+=+.45+\"$
\n" ); document.write( "You can check
\n" ); document.write( " \n" ); document.write( "

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