document.write( "Question 201288: A fish swim 8 miles downstream in two hours. he return upstream in 14 hours. how fast does the fish swim in still water ? \n" ); document.write( "

Algebra.Com's Answer #151516 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"f\"$ = fish's speed in still water in mi/hr
\n" ); document.write( "Let $\"c\"$ = speed of current in mi/hr
\n" ); document.write( "------------
\n" ); document.write( "Given:
\n" ); document.write( " $\"2\"$ hrs = time to go $\"8\"$ mi downstream
\n" ); document.write( " $\"14\"$ hrs = time to go $\"8\"$ mi upstream
\n" ); document.write( "------------
\n" ); document.write( " $\"8+=+%28f+%2B+c%29%2A2\"$ mi
\n" ); document.write( " $\"8+=+%28f+-+c%29%2A14\"$ mi
\n" ); document.write( "and
\n" ); document.write( "(1) $\"8+=+2f+%2B+2c\"$
\n" ); document.write( "(2) $\"8+=+14f+-+14c\"$
\n" ); document.write( "Multiply both sides of (1) by $\"7\"$ and
\n" ); document.write( "add the equations
\n" ); document.write( "(1) $\"56+=+14f+%2B+14c\"$
\n" ); document.write( "(2) $\"8+=+14f+-+14c\"$
\n" ); document.write( " $\"28f+=+64\"$
\n" ); document.write( " $\"f+=+2.286\"$ mi/hr answer
\n" ); document.write( "check answer:
\n" ); document.write( " $\"8+=+%28f+%2B+c%29%2A2\"$
\n" ); document.write( " $\"8+=+%282.286+%2B+c%29%2A2\"$
\n" ); document.write( " $\"8+=+4.571+%2B+2c\"$
\n" ); document.write( " $\"2c+=+3.429\"$
\n" ); document.write( " $\"c+=+1.714\"$ mi/hr
\n" ); document.write( "and
\n" ); document.write( " $\"8+=+%28f+-+c%29%2A14\"$
\n" ); document.write( " $\"8+=+%282.286+-+1.714%29%2A14\"$
\n" ); document.write( " $\"8+=+.572%2A14\"$
\n" ); document.write( " $\"8+=+8.008\"$ close enough\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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