document.write( "Question 384465: A boat's crew rowed 7.5miles downstream, with the current, in 1.5hours. The return trip upstream, against the current, covered the same distance, but took 2.5 hours. Find the crew's rowing rate in still water and the rate of the currnet.
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\n" ); document.write( "The rate of the current is ____ mile(s) per hour. \n" ); document.write( "

Algebra.Com's Answer #272198 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!


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document.write( "Hi,   
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document.write( "D = r*t      
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document.write( "Let (x+c) and (x-c) represent speed downstream and upstream respectively
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document.write( "Question states
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document.write( " 7.5mi = 1.5hrs(x+c) solving for x
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document.write( " 7.5/1.5 - c = x
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document.write( "     5 -c = x\r
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document.write( "7.5(x-c) = 2.5hr  
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document.write( "    (x-c) = 2.5/7.5   substituting for x to solve for c
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document.write( "    [(5-c) - c] = 1/3
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document.write( "        5 - 2c = 1/3
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document.write( "        15/3 - 1/3 = 2c
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document.write( "         14/3 = 2c
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document.write( "           c = 7/3 or 2 1/3mph  the speed of the current
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document.write( "           x = 2 2/3mph  the speed of the boat in still water
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document.write( "CHECKING our Answer
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document.write( "  3/2hr * 5mph = 15/2 = 7.5mi
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