document.write( "Question 925665: A vending machine takes only 20p and 50p coins and contains a total of twenty four
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Algebra.Com's Answer #563249 by Edwin McCravy(20064)\"\" \"About 
You can put this solution on YOUR website!
A vending machine takes only 20p and 50p coins and contains
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document.write( "Let the number of 20p coins be x\r\n" );
document.write( "Then the number of 50p coins, using\r\n" );
document.write( "ONE PART = TOTAL MINUS OTHER PART,\r\n" );
document.write( "is 24-x.\r\n" );
document.write( "                      Value      Value\r\n" );
document.write( "Type       Number       of         of\r\n" );
document.write( " of          of        EACH       ALL\r\n" );
document.write( "coin        coins      coin      coins\r\n" );
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document.write( "20p          x        £0.20    £0.20x\r\n" );
document.write( "50p        24-x       £0.50    £0.50(24-x)\r\n" );
document.write( "-------------------------------------------\r\n" );
document.write( "TOTALS      24        -----    £6.90\r\n" );
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document.write( " The equation comes from the column on the right\r\n" );
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document.write( "  \"%28matrix%285%2C1%2CValue%2Cof%2CALL%2C20p%2Ccoins%29%29\"\"%22%22%2B%22%22\"\"%28matrix%285%2C1%2CValue%2Cof%2CALL%2C50p%2Ccoins%29%29\"\"%22%22=%22%22\"\"%28matrix%284%2C1%2CTotal%2Cvalue%2Cof%2Ccoins%29%29\"\r\n" );
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document.write( "0.20x + 0.50(24-x) = 6.90\r\n" );
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document.write( "Get rid of decimals by multiplying every term by 100\r\n" );
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document.write( "     20x + 50(24-x) = 690\r\n" );
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document.write( "   20x + 1200 - 50x = 690\r\n" );
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document.write( "        -30x + 1200 = 690\r\n" );
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document.write( "               -30x = -510\r\n" );
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document.write( "                  x = 17 = the number of 20p coins\r\n" );
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document.write( "The number of 50p is 24-x or 24-17 or 7 50p coins.\r\n" );
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document.write( "Checking:  17 20p coins is £3.40 and 7 50p is £3.50\r\n" );
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document.write( "And indeed £3.40+£3.50 = £6.90.\r\n" );
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document.write( "Edwin
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