document.write( "Question 805026: Andrea requires 30 minutes to swim 15 miles downstream. The return trip upstream takes 50 minutes.What is Andrea's speed in still water? How fast is the curret in miles per hour? \n" ); document.write( "

Algebra.Com's Answer #485049 by mananth(16946) $\"\"$ $\"About$

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swimming speed =x mph
\n" ); document.write( "current speed =y mph
\n" ); document.write( "against current 0.75 hours
\n" ); document.write( "with current 0.5 hours
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\n" ); document.write( "Distance with current 15 miles distance against current 15
\n" ); document.write( "t=d/r against current (x-y)
\n" ); document.write( "15.00 / ( x - y )= 0.75
\n" ); document.write( "
\n" ); document.write( "0.75 x - -0.75 y = 15.00 ....................1
\n" ); document.write( "with current (x+y)
\n" ); document.write( "15.00 / ( x + y )= 0.50
\n" ); document.write( "0.50 ( x + y ) = 15.00
\n" ); document.write( "0.50 x + 0.50 y = 15.00 ...............2
\n" ); document.write( "Multiply (1) by 0.50
\n" ); document.write( "Multiply (2) by 0.75
\n" ); document.write( "we get 2.00
\n" ); document.write( "0.38 x + -0.38 y = 7.50
\n" ); document.write( "0.38 x + 0.38 y = 11.25
\n" ); document.write( "0.75 x = 18.75
\n" ); document.write( "/ 0.75
\n" ); document.write( "x = 25 mph
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1) y
\n" ); document.write( "0.75 x -0.75 y = 15
\n" ); document.write( "18.75 -0.75 -18.75 = 15
\n" ); document.write( "-0.75 y = 15
\n" ); document.write( "-0.75 y = -3.75 mph
\n" ); document.write( " y = 5
\n" ); document.write( "swimming 25 mph
\n" ); document.write( "current 5 mph
\n" ); document.write( " \n" ); document.write( "

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