document.write( "Question 538068: jessica drove her speedboat upriver this morning. it took her 1 hour going upriver and 54 minutes going downriver. if she traveled 36 miles each way, what would have been the rate of the boat in still water and what was the rate of the current in miles per hour? \n" ); document.write( "
Algebra.Com's Answer #353096 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 1.00 hours
\n" ); document.write( "With current x+y 0.90 hours
\n" ); document.write( "
\n" ); document.write( "Distance = same= 36 miles
\n" ); document.write( "t=d/r
\n" ); document.write( "36 / ( x - y )= 1.00
\n" ); document.write( "1 ( x - y ) = 36.00
\n" ); document.write( "1 x -1 y = 36 ....................1
\n" ); document.write( "36 / ( x + y )= 0.90
\n" ); document.write( "0.90 ( x + y ) = 36
\n" ); document.write( "0.90 x + 0.90 y = 36 ...............2
\n" ); document.write( "Multiply (1) by 0.90
\n" ); document.write( "Multiply (2) by 1.00
\n" ); document.write( "we get
\n" ); document.write( "0.9 x + -0.9 y = 32.4
\n" ); document.write( "0.9 x + 0.9 y = 36
\n" ); document.write( "1.8 x = 68.4
\n" ); document.write( "/ 1.8
\n" ); document.write( "x = 38 mph
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "1 x -1 y = 36
\n" ); document.write( "38 -1 y = 36
\n" ); document.write( "-1 y = 36 -38
\n" ); document.write( "-1 y = -2
\n" ); document.write( " y = 2 mph
\n" ); document.write( " Boat 38 mph
\n" ); document.write( " current 2 mph
\n" ); document.write( " \n" ); document.write( "
\n" );