document.write( "Question 1184398: Andy can buy 3 mechanical pencils with 2/7 of his money. He can buy 6 mechanical pencils and 3 pens with the rest of his money. If he only buys pens, how many pens can he buy with all his money? \n" ); document.write( "

Algebra.Com's Answer #814967 by ikleyn(52778) $\"\"$ $\"About$

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\n" ); document.write( "Andy can buy 3 mechanical pencils with 2/7 of his money.
\n" ); document.write( "He can buy 6 mechanical pencils and 3 pens with the rest of his money.
\n" ); document.write( "If he only buys pens, how many pens can he buy with all his money?
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document.write( "Let x be the price of a pencil and y be the price of a pen.\r\n" );
document.write( "Let M be amount of money Andy has.\r\n" );
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document.write( "Then, interpreting the problem literally as it is written, we have these two equations\r\n" );
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document.write( "    3x =            (1)\r\n" );
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document.write( "    6x + 3y =       (2)\r\n" );
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document.write( "Based on the first equation, I can replace 6x in the second equation by  .  So, I do it, and I get\r\n" );
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document.write( "     + 3y = .\r\n" );
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document.write( "It gives \r\n" );
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document.write( "    3y =  -  = .\r\n" );
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document.write( "THEREFORE,\r\n" );
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document.write( "     = 3*7 = 21.\r\n" );
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document.write( "But  is exactly the number of pens to buy.\r\n" );
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document.write( "HENCE,  Andy can buy  21  pens with all his money.    ANSWER\r\n" );
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