document.write( "Question 1129054: Alvin paddled for 3 hours with a 5-km/h current to reach a campsite. The return trip against the same current took 8 hours. Find the speed of the boat in still water. \n" ); document.write( "

Algebra.Com's Answer #745605 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+s+\"$ = speed of boat in still water
\n" ); document.write( " $\"+s+%2B+5+\"$ = speed going with the current
\n" ); document.write( " $\"+s+-+5+\"$ = speed going against the current
\n" ); document.write( "Let $\"+d+\"$ = the one-way distance
\n" ); document.write( "----------------------------------------------------
\n" ); document.write( "Going with the current:
\n" ); document.write( "(1) $\"+d+=+%28+s+%2B+5+%29%2A3+\"$
\n" ); document.write( "Going against the current:
\n" ); document.write( "(2) $\"+d+=+%28+s+-+5+%29%2A8+\"$
\n" ); document.write( "--------------------------------
\n" ); document.write( " $\"+%28+s+%2B+5+%29%2A3+=+%28+s+-+5+%29%2A8+\"$
\n" ); document.write( " $\"+3s+%2B+15+=+8s+-+40+\"$
\n" ); document.write( " $\"+5s+=+55+\"$
\n" ); document.write( " $\"+s+=+11+\"$
\n" ); document.write( "The speed in still water is 11 km/hr
\n" ); document.write( "-------------------------------------------
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+d+=+%28+11+%2B+5+%29%2A3+\"$
\n" ); document.write( "(1) $\"+d+=+48+\"$ km
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+d+=+%28+11+-+5+%29%2A8+\"$
\n" ); document.write( "(2) $\"+d+=+48+\"$ km
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );