document.write( "Question 1185586: A coffee company wants a new flavor of Cajun coffee. How many pounds of coffee worth $7 a pound should be added to 30 pounds of coffee worth $3 a pound to get a mixture worth $5 a pound?
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Algebra.Com's Answer #816408 by ikleyn(52803) $\"\"$ $\"About$

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document.write( "Let \"p\" be the pounds added.\r\n" );
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document.write( "Then you have this money equation\r\n" );
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document.write( "    7p + 3*30 = 5*(30+p).\r\n" );
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document.write( "Simplify and find p\r\n" );
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document.write( "    7p + 90 = 150 + 5p\r\n" );
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document.write( "    7p - 5p = 150 - 90\r\n" );
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document.write( "       2p   =    60 \r\n" );
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document.write( "        p   =    60/2 = 30.\r\n" );
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document.write( "ANSWER.  30 pounds should be added.\r\n" );
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document.write( "CHECK.   The ingredients cost, in total, 7*30 + 3*30 = 210 + 90 = 300 dollars.\r\n" );
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document.write( "                The mixture costs  5*(30+30) = 5*60 = 300  dollars.   ! Correct !\r\n" );
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\n" ); document.write( "\n" ); document.write( "You may notice that the numbers $3, $5 and $7 dollars make a remarkable sequence: the middle $5 is midway between $3 and $7.\r
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\n" ); document.write( "\n" ); document.write( "Therefore, you may expect that the amounts of the ingredients to mix are the same: 30 pounds.\r
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\n" ); document.write( "\n" ); document.write( "It is the way how to guess the answer MENTALLY, without making calculations.\r
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