document.write( "Question 848267: A riverboat can travel downstream from port A to port B at 20 mph. It can travel upstream from port B to port A at 15 mph. If it takes 5 hours to go upstream than downstream, what is the distance between ports A and B? \n" ); document.write( "

Algebra.Com's Answer #510984 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+t+\"$ = the time in hours to go downstream
\n" ); document.write( " $\"+t+%2B+5+\"$ = the time to go upstream
\n" ); document.write( "Let $\"+d+\"$ = the distance in miles from A to B
\n" ); document.write( "------------------
\n" ); document.write( "Equation for going downstream:
\n" ); document.write( "(1) $\"+d+=+20t+\"$
\n" ); document.write( "Equation for going upstream:
\n" ); document.write( "(2) $\"+d+=+15%2A%28+t+%2B+5+%29+\"$
\n" ); document.write( "----------------------
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+20t+=+15t+%2B+75+\"$
\n" ); document.write( "(2) $\"+5t+=+75+\"$
\n" ); document.write( "(2) $\"+t+=+15+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+d+=+20t+\"$
\n" ); document.write( "(1) $\"+d+=+20%2A15+\"$
\n" ); document.write( "(1) $\"+d+=+300+\"$
\n" ); document.write( "the distance between A an B is 300 mi
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+d+=+20t+\"$
\n" ); document.write( "(2) $\"+300+=+20t+\"$
\n" ); document.write( "(2) $\"+t+=+15+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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