document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=256224>Question 256224</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A motorboat can go 16 miles downstream on a river in 20 minutes. It takes 30 minutes for this boat to go back upstream the same 16 miles. \r<BR>\n" );
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document.write( "a. Write an equation for the motion of the motorboat downstream. <BR>\n" );
document.write( "b. Write an equation for the motion of the motorboat upstream. <BR>\n" );
document.write( "c. Find the speed of the current.\r<BR>\n" );
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document.write( "i'v bin trying to figure this out for soo long plz help :)   </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #188392 by </B><A HREF=/tutors/aboutme.mpl?userid=palanisamy><B>palanisamy(496)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=palanisamy><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=188392\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let the speed of the boat in still water = x<BR>\n" );
document.write( "And the speed of the stream              = y<BR>\n" );
document.write( "When the boat goes downstream, the resultant speed = x+y<BR>\n" );
document.write( "Given,A motorboat can go 16 miles downstream on a river in 20 minutes. <BR>\n" );
document.write( "1) So we have, distance = speed*time<BR>\n" );
document.write( "                     16 = (x+y)*(20/60)<BR>\n" );
document.write( "                     16 = (x+y)*(1/3)<BR>\n" );
document.write( "                     48 = x+y<BR>\n" );
document.write( "                     x+y=48    ...(1)<BR>\n" );
document.write( "2) When the boat goes upstream, the resultant speed = x-y<BR>\n" );
document.write( "It takes 30 minutes for this boat to go back upstream the same 16 miles.<BR>\n" );
document.write( "So we have, distance = speed*time<BR>\n" );
document.write( "                     16 = (x-y)*(30/60)<BR>\n" );
document.write( "                     16 = (x-y)*(1/2)<BR>\n" );
document.write( "                     32 = x-y<BR>\n" );
document.write( "                     x-y=32    ...(2)<BR>\n" );
document.write( "3) Solving (1) and (2),<BR>\n" );
document.write( "(1)+(2)=>            2x = 48+32<BR>\n" );
document.write( "                     2x = 80<BR>\n" );
document.write( "                      x = 80/2<BR>\n" );
document.write( "                      x = 40<BR>\n" );
document.write( "Substituting in (1), we get<BR>\n" );
document.write( "                    40+y = 48<BR>\n" );
document.write( "                       y = 48-40<BR>\n" );
document.write( "                       y = 8     <BR>\n" );
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