document.write( "Question 551669: A pump boat moves at an average speed of 40 kilometers per hour. Suppose it can cover a certain distance in 2hours. if it is moving in the direction of the current and in 2 1/2 hours if it is moving against the current. What is the speed of the current? \n" ); document.write( "
Algebra.Com's Answer #359842 by mananth(16946)\"\" \"About 
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Boat speed = 40 km/h
\n" ); document.write( "current speed = x km/h
\n" ); document.write( "wind speed
\n" ); document.write( "speed against current 40 -x
\n" ); document.write( "speed with current 40 +x
\n" ); document.write( "
\n" ); document.write( "Distance against current x km
\n" ); document.write( "Distance with current x km\r
\n" ); document.write( "\n" ); document.write( "time with current = 2 hours
\n" ); document.write( "y/(40+x) =2
\n" ); document.write( "y=2(40+x)
\n" ); document.write( "y=80+2x..........(1)\r
\n" ); document.write( "\n" ); document.write( "Time against current = 2 1/2 hours
\n" ); document.write( "y/(40-x)=5/2
\n" ); document.write( "y= 5(40-x)/2............(2)\r
\n" ); document.write( "\n" ); document.write( "equate equation (1) & (2)
\n" ); document.write( "80+2x=5(40-x)/2
\n" ); document.write( "multiply by 2
\n" ); document.write( "160+4x=200-5x
\n" ); document.write( "9x=40
\n" ); document.write( "/9
\n" ); document.write( "x=40/9\r
\n" ); document.write( "\n" ); document.write( "x=4.44 km/h speed of current\r
\n" ); document.write( "\n" ); document.write( "m.ananth@hotmail.ca\r
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