document.write( "Question 522559: Traveling downstream, a boat can go 12 miles in 2 hours. Going upstream, it makes only 2/3 this distance in twice the time. What is the rate of the boat in still water, and what is the rate of the current? \n" ); document.write( "

Algebra.Com's Answer #346915 by mananth(16946) $\"\"$ $\"About$

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downstream, a boat can go 12 miles in 2 hours. \r
\n" ); document.write( "\n" ); document.write( "Going upstream, 12* 2/3 =>8 miles in 4 hours \r
\n" ); document.write( "\n" ); document.write( "let boat speed = x
\n" ); document.write( "current speed =y\r
\n" ); document.write( "\n" ); document.write( "upstream speed = x-y
\n" ); document.write( "down stream speed = x+y
\n" ); document.write( "d/r=t
\n" ); document.write( "downstream
\n" ); document.write( "12/(x+y)=2
\n" ); document.write( "2x+2y=12
\n" ); document.write( "x+y=6.....1
\n" ); document.write( "upstream
\n" ); document.write( "8/(x-y)=4
\n" ); document.write( "4x-4y=8
\n" ); document.write( "x-y=4...........2
\n" ); document.write( "Add equation (1) & (2)
\n" ); document.write( "2x=10
\n" ); document.write( "x=5 mph
\n" ); document.write( "so y= 1\r
\n" ); document.write( "\n" ); document.write( "Boat speed = 5 mph, current speed = 1mph\r
\n" ); document.write( "\n" ); document.write( "m.ananth@hotmail.com \n" ); document.write( "

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