document.write( "Question 1121502: A speedboat moves at a rate of 21 km/hr in still water. how long will it take someone to rise the boat 60 km downstream if the rivers current moves at a rate of 9 km/hr? \n" ); document.write( "

Algebra.Com's Answer #737397 by ikleyn(52797) $\"\"$ $\"About$

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document.write( "The effective speed downstream is the sum of speeds\r\n" );
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document.write( "    21 km/h + 9 km/h = 30 km/h.        <<<---=== it is the speed relative to the river banks.\r\n" );
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document.write( "The time to travel 60 km downstream is   = 2 hours.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Answer. 2 hours.\r
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