document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=859490>Question 859490</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A ship travel from port A to port B with distance 20 knots in 30 minutes.the ship travel back from port B to port A in 20 minutes. What is the average speed of the round trip in km/hr. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #517858 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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/cgi-bin/show-face.mpl?user=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=517858\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A ship travel from port A to port B with distance 20 km in 30 minutes.<BR>\n" );
document.write( "the ship travel back from port B to port A in 20 minutes.<BR>\n" );
document.write( " What is the average speed of the round trip in km/hr.<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Let a = average speed for the trip in km/h<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Assuming the one-way distance is 20 km<BR>\n" );
document.write( "Change 30 min to 1/2 hr, and 20 min to 1/3 hr<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Find the speed  A-B and B-A<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20%2F%281%2F2%29 ALIGN=MIDDLE  ALT=\"20%2F%281%2F2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 40 km/hr<BR>\n" );
document.write( ":<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20%2F%281%2F3%29 ALIGN=MIDDLE  ALT=\"20%2F%281%2F3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 60 km/hr<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a time equation; time = dist/speed<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20%2F40 ALIGN=MIDDLE  ALT=\"20%2F40\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20%2F60 ALIGN=MIDDLE  ALT=\"20%2F60\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40%2Fa ALIGN=MIDDLE  ALT=\"40%2Fa\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply by 120a to clear the denominator, results<BR>\n" );
document.write( "3a(20) + 2a(20) = 120(40)<BR>\n" );
document.write( "60a + 40a = 4800<BR>\n" );
document.write( "100a = 4800<BR>\n" );
document.write( "a = 4800/100<BR>\n" );
document.write( "a = 48 km/hr av speed for the round trip<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );