document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1199506>Question 1199506</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A boat travelled 32 miles downstream and then made the return trip. The trip with the current took 1 hour whereas the trip back against the current took 4 hours. What was the speed of the boat in still water and what was the speed of the current?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #833426 by </B><A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><B>math_tutor2020(3817)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><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=833426\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "b = speed of the boat in still water<BR>\n" );
document.write( "c = speed of the current<BR>\n" );
document.write( "Speeds are in mph\r<BR>\n" );
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document.write( "Downstream:<BR>\n" );
document.write( "The boat speeds up to go from b to b+c<BR>\n" );
document.write( "It travels the 32 mile distance in 1 hour<BR>\n" );
document.write( "distance = rate*time<BR>\n" );
document.write( "32 = (b+c)*1<BR>\n" );
document.write( "32 = b+c<BR>\n" );
document.write( "b = 32-c\r<BR>\n" );
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document.write( "Upstream:<BR>\n" );
document.write( "The boat is slowed down go from b to b-c<BR>\n" );
document.write( "This time it takes 4 hours.<BR>\n" );
document.write( "distance = rate*time<BR>\n" );
document.write( "32 = (b-c)*4<BR>\n" );
document.write( "32 = (32-c-c)*4 ..... plug in b = 32-c<BR>\n" );
document.write( "32 = (32-2c)*4<BR>\n" );
document.write( "32 = 128-8c<BR>\n" );
document.write( "32+8c = 128<BR>\n" );
document.write( "8c = 128-32<BR>\n" );
document.write( "8c = 96<BR>\n" );
document.write( "c = 96/8<BR>\n" );
document.write( "c = 12<BR>\n" );
document.write( "The speed of the current is 12 mph.\r<BR>\n" );
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document.write( "Then lastly,<BR>\n" );
document.write( "b = 32-c<BR>\n" );
document.write( "b = 32-12<BR>\n" );
document.write( "b = 20<BR>\n" );
document.write( "The boat's speed in still water is 20 mph.\r<BR>\n" );
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document.write( "b = 20 = speed of the boat in still water<BR>\n" );
document.write( "c = 12 = speed of the current\r<BR>\n" );
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document.write( "b+c = 20+12 = 32 mph is the boat's speed when going downstream, when the boat is given a helpful push by the water.\r<BR>\n" );
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document.write( "Then note how<BR>\n" );
document.write( "distance = rate*time<BR>\n" );
document.write( "32 = 32*1<BR>\n" );
document.write( "32 = 32<BR>\n" );
document.write( "Confirming the downstream equation is correct.\r<BR>\n" );
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document.write( "b-c = 20-12 = 8 mph is the upstream speed.<BR>\n" );
document.write( "distance = rate*time<BR>\n" );
document.write( "32 = 8*4<BR>\n" );
document.write( "32 = 32<BR>\n" );
document.write( "The upstream equation is confirmed also.\r<BR>\n" );
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document.write( "Answers:\r<BR>\n" );
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document.write( "Speed of the boat in still water = <font color=red>20 mph</font><BR>\n" );
document.write( "Speed of the current = <font color=red>12 mph</font><BR>\n" );
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