document.write( "Question 1172386: A shopkeeper bought some dozens of exercise books at ₦20.00 each. He found 13 of them torn, but he sells the rest at ₦32.00 each and makes a profit of ₦88.00. How many dozen of exercise book did he buy? \n" ); document.write( "

Algebra.Com's Answer #797453 by ikleyn(52803) $\"\"$ $\"About$

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document.write( "Let x be the number of dozens of exercise books bought.\r\n" );
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document.write( "Then the number of books bought was  12x.\r\n" );
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document.write( "The number of books sold is  (12x - 13). \r\n" );
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document.write( "The money equation for the profit is easy to write.  It is\r\n" );
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document.write( "    (12x-13)*32 = 12x*20 + 88.\r\n" );
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document.write( "From this equation\r\n" );
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document.write( "    12x*32 - 12x*20  = 88 + 13*32,   or\r\n" );
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document.write( "    (12*32 - 12*20)x = 504\r\n" );
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document.write( "         144x        = 504\r\n" );
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document.write( "            x        =  = 3.5.\r\n" );
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document.write( "ANSWER.  3.5  dozens of books were bought.\r\n" );
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document.write( "         //  3.5 dozens is 12*3.5 = 42 books, so there is no reason to worry about the integer number of books.\r\n" );
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