document.write( "Question 48323: 
Travelling at full speed agaist the current of a river, a \r\n" );
document.write( "motorboat moves at the rate of 12 kilometers per hour relative\r\n" );
document.write( "to the land.  Travelling at half speed with the current, it \r\n" );
document.write( "moves 8 kilometers per hour. find the maximum speed of the boat \r\n" );
document.write( "in still water.
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Algebra.Com's Answer #31953 by AnlytcPhil(1806)\"\" \"About 
You can put this solution on YOUR website!
Travelling at full speed agaist the current of a river, a \r\n" );
document.write( "motorboat moves at the rate of 12 kilometers per hour relative\r\n" );
document.write( "to the land.  Travelling at half speed with the current, it \r\n" );
document.write( "moves 8 kilometers per hour. find the maximum speed of the boat \r\n" );
document.write( "in still water.\r\n" );
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document.write( "Let x = maximum speed in still water in k/h\r\n" );
document.write( "Let y = speed of the river current in k/h.\r\n" );
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document.write( "The river current slows the boat down from speed x k/h \r\n" );
document.write( "to x-y k/h, so\r\n" );
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document.write( ">>...travelling at full speed agaist the current of a river, \r\n" );
document.write( "a motorboat moves at the rate of 12 kilometers per hour relative \r\n" );
document.write( "to the land...<<\r\n" );
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document.write( "tells us  \r\n" );
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document.write( "x - y = 12\r\n" );
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document.write( "When the boat travels at half speed with the current, the current\r\n" );
document.write( "speeds up the boat from half speed (1/2)x k/h to (1/2)x+y k/h, so\r\n" );
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document.write( ">>...travelling at half speed with the current, it moves 8 \r\n" );
document.write( "kilometers per hour...<<\r\n" );
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document.write( "tells us\r\n" );
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document.write( "(1/2)x + y = 8\r\n" );
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document.write( "so we have this system of 2 equations in 2 unknowns:\r\n" );
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document.write( "     x - y = 12\r\n" );
document.write( "(1/2)x + y = 8\r\n" );
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document.write( "Can you solve that?\r\n" );
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document.write( "x = 40/3 k/h, y = 4/3 k/h\r\n" );
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document.write( "So the boat goes 13 1/3 k/h in still water, and the \r\n" );
document.write( "current's speed is 1 1/3 k/h\r\n" );
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document.write( "Edwin
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