document.write( "Question 565874: A boat travels 60km upstream (against the current) in 5 hours. The boat travels the same distance downstream in 3 hours. What is the rate of the boat in still water? What is the rate of the current? \n" ); document.write( "

Algebra.Com's Answer #366015 by mananth(16946) $\"\"$ $\"About$

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Boat speed =x mph
\n" ); document.write( "current speed =y mph
\n" ); document.write( "against current x-y 5.00 hours
\n" ); document.write( "with current x+y 3.00 hours
\n" ); document.write( "
\n" ); document.write( "Distance = same= 60 km
\n" ); document.write( "t=d/r
\n" ); document.write( "60 / ( x - y )= 5.00
\n" ); document.write( "5 ( x - y ) = 60.00
\n" ); document.write( "5 x -5 y = 60 ....................1
\n" ); document.write( "60 / ( x + y )= 3.00
\n" ); document.write( "3.00 ( x + y ) = 60
\n" ); document.write( "3.00 x + 3.00 y = 60 ...............2
\n" ); document.write( "Multiply (1) by 3.00
\n" ); document.write( "Multiply (2) by 5.00
\n" ); document.write( "we get
\n" ); document.write( "15 x + -15 y = 180
\n" ); document.write( "15 x + 15 y = 300
\n" ); document.write( "30 x = 480
\n" ); document.write( "/ 30
\n" ); document.write( "x = 16 mph
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "5 x -5 y = 60
\n" ); document.write( "80 -5 y = 60
\n" ); document.write( "-5 y = 60 -80
\n" ); document.write( "-5 y = -20
\n" ); document.write( " y = 4 mph
\n" ); document.write( "The speed of Boat = 16 mph
\n" ); document.write( "The speed of current = 4 mph
\n" ); document.write( " \n" ); document.write( "

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