Algebra.Com's Answer #819339 by ikleyn(52795)![\"\"](\"/images/stars/stars-13.gif\")  
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document.write( "Justin spent 3/10 of his money on 11 packs of cards. He would be able to
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document.write( "buy another 29 such packs of cards with the remaining amount of his
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document.write( "money and an additional $20.
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document.write( "(a) What was the price of 1 pack of cards?
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document.write( "(b) How much money did Justin have at first?
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document.write( "Let x be the amount Justin had at first.\r\n" );
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document.write( "He spent 0.3x to buy 11 packs of cards; hence, each pack costs  dollars.\r\n" );
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document.write( "After spending 3/10 of his money, he still have 0.7x of his money remainder.\r\n" );
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document.write( "Next you write the equation as you read the problem\r\n" );
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document.write( " 0.7x + 20 =  .\r\n" );
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document.write( "It is your basic equation to solve and to find x.\r\n" );
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document.write( "To solve it, multiply both sides by 110. You will get\r\n" );
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document.write( " 77x + 2200 = 29*3x\r\n" );
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document.write( " 2200 = 29*3x - 77x\r\n" );
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document.write( " 2200 = 10x\r\n" );
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document.write( " x = 2200/10 = 220 dollars.\r\n" );
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document.write( "So, Justin had 220 dollars, at first.\r\n" );
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document.write( "3/10 of 220 dollars is 3*22 = 66 dollars.\r\n" );
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document.write( "Since Justin bought 11 packs of cards for 66 dollars, each pack of cards costs 66/11 = 6 dollars.\r\n" );
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document.write( "Solved.\r
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document.write( "So, you can easily solve the problem using only one single equation for one single unknown,\r
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document.write( "as if you knows NOTHING about systems of equations.\r
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