document.write( "Question 510872: A salmon fishing boat on a BC river travelled 96 km upstream (against the current in 4h. Returning downstream at the same speed, it took 3h. Find the speed of the fishing boat in still water and the speed of the river's current \n" ); document.write( "

Algebra.Com's Answer #341894 by mananth(16946) $\"\"$ $\"About$

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Boat speed speed =x mph
\n" ); document.write( "current speed speed =y mph
\n" ); document.write( "against wind x-y 4.00 hours
\n" ); document.write( "With current x+y 3.00 hours
\n" ); document.write( "
\n" ); document.write( "Distance = same= 96 miles
\n" ); document.write( "t=d/r
\n" ); document.write( "96 / ( x - y )= 4.00
\n" ); document.write( "4 ( x - y ) = 96.00
\n" ); document.write( "4 x -4 y = 96 ....................1
\n" ); document.write( "96 / ( x + y )= 3.00
\n" ); document.write( "3.00 ( x + y ) = 96
\n" ); document.write( "3.00 x + 3.00 y = 96 ...............2
\n" ); document.write( "Multiply (1) by 3.00
\n" ); document.write( "Multiply (2) by 4.00
\n" ); document.write( "we get
\n" ); document.write( "12 x + -12 y = 288
\n" ); document.write( "12 x + 12 y = 384
\n" ); document.write( "24 x = 672
\n" ); document.write( "/ 24
\n" ); document.write( "x = 28 mph
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "4 x -4 y = 96
\n" ); document.write( "112 -4 y = 96
\n" ); document.write( "-4 y = 96 -112
\n" ); document.write( "-4 y = -16
\n" ); document.write( " y = 4 mph
\n" ); document.write( " \n" ); document.write( "

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