document.write( "Question 775035: speed of boat in still water is 10km/hr .if it can travel 26km down stream and 14km upstream in same time. find the speed of stream. \n" ); document.write( "

Algebra.Com's Answer #472624 by Edwin McCravy(20059) $\"\"$ $\"About$

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\n" ); document.write( "speed of boat in still water is 10km/hr. If it can
\n" ); document.write( "travel 26km downstream and 14km upstream in same time.
\n" ); document.write( "Find the speed of stream.
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document.write( "Let the rate of the stream be x km/h.\r\n" );
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document.write( "The boat's rate when the river speeds up the boat by \r\n" );
document.write( "adding its speed of x km/h to the boat's speed giving\r\n" );
document.write( "10+x km/h.\r\n" );
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document.write( "The boat's rate when the river slows the boat down and\r\n" );
document.write( "subtracts its speed of x km/h from the boat's speed \r\n" );
document.write( "giving 10-x km/h.\r\n" );
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document.write( "Time = Distance/Rate\r\n" );
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document.write( "Downstream time = (Downstream Distance)/rate = 26/(10+x)\r\n" );
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document.write( "Upstream time = (Upstream Distance)/rate = 14/(10-x)\r\n" );
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document.write( "Those times are equal.\r\n" );
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document.write( "26/(10+x) = 14/(10-x)\r\n" );
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document.write( "Might as well divide both sides by 2\r\n" );
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document.write( "13/(10+x) = 7/(10-x)\r\n" );
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document.write( "Cross-multiply:\r\n" );
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document.write( "13(10-x) = 7(10+x)\r\n" );
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document.write( "130-13x = 70+7x\r\n" );
document.write( "   -20x = -60\r\n" );
document.write( "      x = 3 km/h\r\n" );
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document.write( "That's the answer.  The rate of the river is 3 km/h.  The story\r\n" );
document.write( "is that he went down the river at 13 km/h for 26 km. for the \r\n" );
document.write( "first 2 hours and came back at a slower 7 km/hr and only made \r\n" );
document.write( "it 14 km of the way back when the second 2 hours was up.  \r\n" );
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document.write( "Edwin

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