document.write( "Question 952783: In 6 hours two men can row 16 miles downstream on a river and back. their rate upstream is twice the rate of the current. find the rate at which they row in still water and the rate of the current. I hope you could help me. this is in a chapter in our book concerning word problems on simultaneous systems involving quadratic. \n" ); document.write( "
Algebra.Com's Answer #581863 by Alan3354(69443)\"\" \"About 
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In 6 hours two men can row 16 miles downstream on a river and back. their rate upstream is twice the rate of the current. find the rate at which they row in still water and the rate of the current.
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\n" ); document.write( "c = current speed
\n" ); document.write( "b = boat's speed wrt the water
\n" ); document.write( "r = rate wrt Earth
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\n" ); document.write( "Upstream, r = b - c = 2c --> b = 3c
\n" ); document.write( "downstream, r = b + c = 4c
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\n" ); document.write( "Avg of the round trip is 2*3c*4c/(3c + 4c) = 24c/7 mi/hr
\n" ); document.write( "RT avg = 2*16/6 = 16/3 mi/hr
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\n" ); document.write( "24c/7 = 16/3
\n" ); document.write( "72c = 112
\n" ); document.write( "c = 14/9 mi/hr
\n" ); document.write( "b = 14/3 mi/hr
\n" ); document.write( "=================
\n" ); document.write( "Check:
\n" ); document.write( "d'stream: r = 56/9 mi/hr --> t = d/r = 16/(56/9) = 18/7 hours
\n" ); document.write( "u'stream: r = 14/3 mi/hr --> t = d/r = 16/(14/3) = 24/7 hours
\n" ); document.write( "18/7 + 24/7 = 6 hours \n" ); document.write( "
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