document.write( "Question 777738: how much 1% milk and how much 4% milk must be combined to obtain 60 liters of 2% milk \n" ); document.write( "

Algebra.Com's Answer #474288 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+a+\"$ = liters of 1% milk needed
\n" ); document.write( "Let $\"+b+\"$ = liters of 4% milk needed
\n" ); document.write( " $\"+.01a+\"$ = liters of fat in 1% milk
\n" ); document.write( " $\"+.04b+\"$ = liters of fat in 4% milk
\n" ); document.write( "------------------------------
\n" ); document.write( "(1) $\"+a+%2B+b+=+60+\"$
\n" ); document.write( "(2) $\"+%28+.01a+%2B+.04b+%29+%2F+60+=+.02+\"$
\n" ); document.write( "-----------------------------
\n" ); document.write( "(2) $\"+.01a+%2B+.04b+=+.02%2A60+\"$
\n" ); document.write( "(2) $\"+.01a+%2B+.04b+=+1.2+\"$
\n" ); document.write( "(2) $\"+a+%2B+4b+=+120+\"$
\n" ); document.write( "-------------------
\n" ); document.write( "Subtract (1) from (2)
\n" ); document.write( "(2) $\"+a+%2B+4b+=+120+\"$
\n" ); document.write( "(1) $\"+-a+-+b+=+-60+\"$
\n" ); document.write( " $\"+3b+=+60+\"$
\n" ); document.write( " $\"+b+=+20+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+a+%2B+b+=+60+\"$
\n" ); document.write( "(1) $\"+a+=+60+-+20+\"$
\n" ); document.write( "(1) $\"+a=+40+\"$
\n" ); document.write( "-------------
\n" ); document.write( "40 liters of 1% milk are needed
\n" ); document.write( "20 liters of 4% milk are needed
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+%28+.01a+%2B+.04b+%29+%2F+60+=+.02+\"$
\n" ); document.write( "(2) $\"+%28+.01%2A40+%2B+.04%2A20+%29+%2F+60+=+.02+\"$
\n" ); document.write( "(2) $\"+%28+.4+%2B+.8+%29+%2F+60+=+.02+\"$
\n" ); document.write( "(2) $\"+1.2+=+.02%2A60+\"$
\n" ); document.write( "(2) $\"+1.2+=+1.2+\"$
\n" ); document.write( "OK \n" ); document.write( "

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