document.write( "Question 548560: A boat travels 28 miles upstream in 4 hours. Going downstream, it can travel 60 miles in the same amount of time. Find the speed of the speed of the current and the speed of the boat in still water. \n" ); document.write( "
Algebra.Com's Answer #357073 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
Boat speed =x mph
\n" ); document.write( "current speed =y mph
\n" ); document.write( "against current , x-y 4 hours
\n" ); document.write( "with current , x+y 4 hours
\n" ); document.write( "
\n" ); document.write( "Distance = same= 2000 miles
\n" ); document.write( "t=d/r against current
\n" ); document.write( "28 / ( x - y )= 4.00
\n" ); document.write( "4 ( x - y ) = 28.00
\n" ); document.write( " With current
\n" ); document.write( "4 x -4 y = 28 ....................1
\n" ); document.write( "60 / ( x + y )= 4.00
\n" ); document.write( "4.00 ( x + y ) = 60
\n" ); document.write( "4.00 x + 4 y = 60 ...............2
\n" ); document.write( "Multiply (1) by 1.00
\n" ); document.write( "Multiply (2) by 1.00
\n" ); document.write( "we get
\n" ); document.write( "4 x + -4 y = 28
\n" ); document.write( "4 x + 4 y = 60
\n" ); document.write( "8 x = 88
\n" ); document.write( "/ 8
\n" ); document.write( "x = 11 mph
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "4 x -4 y = 28
\n" ); document.write( "44 -4 y = 28
\n" ); document.write( "-4 y = 28 -44
\n" ); document.write( "-4 y = -16
\n" ); document.write( " y = 4 mph
\n" ); document.write( " Boat 11 mph
\n" ); document.write( " current 4 mph
\n" ); document.write( "
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( " \n" ); document.write( "
\n" );