document.write( "Question 1031290: A dairy needs 310 gallons of milk containing 6% butterfat. How many gallons each of milk containing 7% butterfat and milk containing 2% butterfat must be used to obtain the desired 310 gallons?
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Algebra.Com's Answer #646055 by ikleyn(52803)\"\" \"About 
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\n" ); document.write( "A dairy needs 310 gallons of milk containing 6% butterfat. How many gallons each of milk containing 7% butterfat and milk
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document.write( "    x +     y = 310,        (1)    (milk volume balance, in liters)\r\n" );
document.write( "0.07x + 0.02y = 0.06*310    (2)    (butterfat balance)\r\n" );
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document.write( "From (1), express y = 310 - x and substitute it into equation (2). You will get\r\n" );
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document.write( "0.07x + 0.02*(310 - x) = 18.6.\r\n" );
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document.write( "Simplify and solve for x:\r\n" );
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document.write( "0.07x + 6.2 - 0.02x = 18.6,\r\n" );
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document.write( "0.05x = 18.6 - 6.2,\r\n" );
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document.write( "0.05x = 12.4,\r\n" );
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document.write( "x = \"12.4%2F0.05\" = 248.\r\n" );
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document.write( "Answer. 248 liters of the 0.06% butterfat and 310-248 = 62 liters of the 0.02% butterfat.\r\n" );
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