document.write( "Question 1115859: A plant food is to be made from three chemicals. The combined amounts of the first two chemicals must be 70% of the resulting mix. The second and third chemicals must be in the ratio of 4 to 3 by weight. How much of each chemical is needed to make 700 kg of the plant food? \n" ); document.write( "

Algebra.Com's Answer #730691 by ikleyn(52802) $\"\"$ $\"About$

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document.write( "Let x = 1st chemical amount (in kilograms);\r\n" );
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document.write( "    y = 2nd chemical amount;\r\n" );
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document.write( "    z = 3rd chemical amount.\r\n" );
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document.write( "From the condition, we have\r\n" );
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document.write( "x + y + z = 700                  (1)\r\n" );
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document.write( "x + y     = 490                  (2)    (70% of 700 kg)\r\n" );
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document.write( "     = ,    or   3y = 4z.     (3)\r\n" );
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document.write( "Subtract eq(2) from eq(1). You will get\r\n" );
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document.write( "    z = 700 - 490 = 210 kg.\r\n" );
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document.write( "Then from (3),  y =  = 280.\r\n" );
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document.write( "Then from (1),  x = 700 - 280 - 210 = 210.\r\n" );
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