document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=971067>Question 971067</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A motorboat traveled 35 km upstream on a river and then up an adjacent stream for 18 km, spending 8 hours on the entire trip. The speed of the river’s current was 1 km/hour slower than the speed of the stream’s current. Find the speed of the current of the river, if the speed of the motorboat in still water is 10 km/hour. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #593747 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=593747\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A motorboat traveled 35 km upstream on a river and then up an adjacent stream for 18 km, spending 8 hours on the entire trip. The speed of the river’s current was 1 km/hour slower than the speed of the stream’s current. Find the speed of the current of the river, if the speed of the motorboat in still water is 10 km/hour.<BR>\n" );
document.write( "***<BR>\n" );
document.write( "let c=speed of river<BR>\n" );
document.write( "speed of stream=(c+1)<BR>\n" );
document.write( "10-c=speed of motorboat upstream on the river<BR>\n" );
document.write( "10-(c+1)=(9-c)=speed of motorboat upstream on adjacent stream<BR>\n" );
document.write( "travel time=distance/speed<BR>\n" );
document.write( "..<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=35%2F%2810-c%29%2B18%2F%289-c%29=8 ALIGN=MIDDLE  ALT=\"35%2F%2810-c%29%2B18%2F%289-c%29=8\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "lcd:(9-c)(10-c)<BR>\n" );
document.write( "35(9-c)+18(10-c)=8(9-c)(10-c)<BR>\n" );
document.write( "315-35c+180-18c=8(90-19c+c^2)<BR>\n" );
document.write( "315-35c+180-18c=720-152c+8c^2<BR>\n" );
document.write( "8c^2-99c+225<BR>\n" );
document.write( "(c-3)(8c-75)=0<BR>\n" );
document.write( "c=9.375(reject)<BR>\n" );
document.write( "or<BR>\n" );
document.write( "c=3<BR>\n" );
document.write( "speed of the current of the river=3 km/hr </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );