document.write( "Question 841990: A boat traveled 315 miles downstream and back. Downstream took 15 hours and going back took 35 hours. What is the boat speed in still water and what is the speed of the current? \n" ); document.write( "

Algebra.Com's Answer #507296 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+s+\"$ = the boat's speed in still water
\n" ); document.write( "Let $\"+c+\"$ = the speed of the current
\n" ); document.write( "---------------------------------
\n" ); document.write( "Equation for going downstream:
\n" ); document.write( "(1) $\"+315+=+%28+s+%2B+c+%29%2A15+\"$
\n" ); document.write( "Equation for going upstream:
\n" ); document.write( "(2) $\"+315+=+%28+s+-+c+%29%2A35+\"$
\n" ); document.write( "------------------------
\n" ); document.write( "(1) $\"+s+%2B+c+=+315%2F15+\"$
\n" ); document.write( "(1) $\"+s+%2B+c+=+21+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+s+-+c+=+315%2F35+\"$
\n" ); document.write( "(2) $\"+s+-+c+=+9+\"$
\n" ); document.write( "--------------------
\n" ); document.write( "Add (1) and (2)
\n" ); document.write( "(1) $\"+s+%2B+c+=+21+\"$
\n" ); document.write( "(2) $\"+s+-+c+=+9+\"$
\n" ); document.write( " $\"+2s+=+30+\"$
\n" ); document.write( " $\"+s+=+15+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+s+-+c+=+9+\"$
\n" ); document.write( "(2) $\"+15+-+c+=+9+\"$
\n" ); document.write( "(2) $\"+c+=+15+-+9+\"$
\n" ); document.write( "(2) $\"+c+=+6+\"$
\n" ); document.write( "------------------
\n" ); document.write( "The boat's speed in still water is 15 mi/hr
\n" ); document.write( "The speed of the current is 6 mi/hr
\n" ); document.write( " \n" ); document.write( "

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