document.write( "Question 1027331: When the piggy bank was full it yielded $4.75 in nickels and pennies. If there were 175 coins in all how many were nickels and how man were pennies?
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Algebra.Com's Answer #642527 by Edwin McCravy(20055) $\"\"$ $\"About$

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document.write( "Let the number of nickels be x\r\n" );
document.write( "Let the number of pennies be y\r\n" );
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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( "nickels        x      $0.05      $0.05x\r\n" );
document.write( "pennies        y      $0.01      $0.01y\r\n" );
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document.write( "TOTALS       175      -----      $4.75\r\n" );
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document.write( " The first equation comes from the second column.\r\n" );
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document.write( "  \r\n" );
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document.write( "                 x + y = 175\r\n" );
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document.write( " The second equation comes from the last column.\r\n" );
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document.write( "           0.05x + 0.01y = 4.75\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( "                 5x + 1y = 475\r\n" );
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document.write( " So we have the system of equations:\r\n" );
document.write( "           .\r\n" );
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document.write( "We solve by substitution.  Solve the first equation for y:\r\n" );
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document.write( "            x + y = 175\r\n" );
document.write( "                y = 175 - x\r\n" );
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document.write( "Substitute (175 - x) for y in 5x + 1y = 475\r\n" );
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document.write( "  5x + 1(175 - x) = 475\r\n" );
document.write( "    5x + 175 - 1x = 475\r\n" );
document.write( "         4x + 175 = 475\r\n" );
document.write( "               4x = 300\r\n" );
document.write( "                x = 75 = the number of nickels.\r\n" );
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document.write( "Substitute in y = 175 - x\r\n" );
document.write( "              y = 175 - (75)\r\n" );
document.write( "              y = 100 pennies.\r\n" );
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document.write( "Checking:  75 nickels is $3.75 and 100 pennies is $1.00\r\n" );
document.write( "            That's 175 coins.\r\n" );
document.write( "            And indeed $3.75 + $1.00 = $4.75\r\n" );
document.write( "Edwin

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