document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=555102>Question 555102</A>: <I><SPAN STYLE=\"word-break: break-all;\"> With a strong wind at its back, a ship can make a 425 mile journey in 90 minutes less than it can without the breeze.  If its average speed is increased by 15 mph with the aid of the wind, about how long did the joutney take with the breeze? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #361702 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=361702\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> With a strong wind at its back, a ship can make a 425 mile journey in 90 minutes less than it can without the breeze.<BR>\n" );
document.write( " If its average speed is increased by 15 mph with the aid of the wind, about how long did the journey take with the breeze?<BR>\n" );
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document.write( "From the information given, we can find the speed of the boat in still water<BR>\n" );
document.write( "Let s = boat speed in still water<BR>\n" );
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document.write( "write a time equation, change 90 min to 1.5 hrs<BR>\n" );
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document.write( "no breeze time - with breeze time = 1.5 hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=425%2Fs ALIGN=MIDDLE  ALT=\"425%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=425%2F%28%28s%2B15%29%29 ALIGN=MIDDLE  ALT=\"425%2F%28%28s%2B15%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 1.5<BR>\n" );
document.write( "Multiply by s(s+15)<BR>\n" );
document.write( "425(s+15) - 425s = 1.5s(s+15)<BR>\n" );
document.write( "425s + 6375 - 425s  = 1.5s^2 + 22.5s<BR>\n" );
document.write( "6375 = 1.5s^2 + 22.5s<BR>\n" );
document.write( "A quadratic equation<BR>\n" );
document.write( "1.5s^2 + 22.5s - 6375 = 0<BR>\n" );
document.write( "Simplify divide by 1.5<BR>\n" );
document.write( "s^2 + 15s - 4250 = 0<BR>\n" );
document.write( "Use the quadratic formula to find the s<BR>\n" );
document.write( "I got a positive solution of s = 58.12 mph<BR>\n" );
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document.write( "\" If its average speed is increased by 15 mph with the aid of the wind, about how long did the journey take with the breeze?\"<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=425%2F%28%2858.12%2B15%29%29 ALIGN=MIDDLE  ALT=\"425%2F%28%2858.12%2B15%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 5.81 hrs<BR>\n" );
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document.write( "Check this by finding the time without the wind<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=425%2F58.12 ALIGN=MIDDLE  ALT=\"425%2F58.12\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 7.31 hrs<BR>\n" );
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document.write( "7.31 - 5.81 = 1.5 hrs </SPAN>\n" );
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