document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1138663>Question 1138663</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Supposed flying in a calm air a robin can reach a speed of 25 kilometers per hour. Each day, this robin flies from its nest to the nearest body of water 1 kilometer away. On one particular day it flew into a headwind and on its return trip the wind was at it's back. if the total trip took 1/10 of an hour, what was the speed of the wind? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #756476 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=756476\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Supposed flying in a calm air a robin can reach a speed of 25 kilometers per hour.<BR>\n" );
document.write( " Each day, this robin flies from its nest to the nearest body of water 1 kilometer away.<BR>\n" );
document.write( " On one particular day it flew into a headwind and on its return trip the wind was at it's back.<BR>\n" );
document.write( " if the total trip took 1/10 of an hour, what was the speed of the wind?<BR>\n" );
document.write( ": <BR>\n" );
document.write( "let w = the speed of the wind<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(25-w) = the ground speed against the wind<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(25+w) = the speed with<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a time equation; time = dist/speed<BR>\n" );
document.write( "to lake time + return time = .1 hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F%28%2825-w%29%29 ALIGN=MIDDLE  ALT=\"1%2F%28%2825-w%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F%28%2825%2Bw%29%29 ALIGN=MIDDLE  ALT=\"1%2F%28%2825%2Bw%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = .1<BR>\n" );
document.write( "multiply equation by (25-w)(25+w), cancel the denominators<BR>\n" );
document.write( "(25+w) + (25-w) = .1(25-w)(25+w)<BR>\n" );
document.write( "25 + 25 + w - w = .1(-w^2 + 625); difference of squares<BR>\n" );
document.write( "50 = -.1w^2 + 62.5<BR>\n" );
document.write( ".1w^2 = 62.5 - 50<BR>\n" );
document.write( ".1w^2 = 12.5<BR>\n" );
document.write( "multiply both sides by 10<BR>\n" );
document.write( "w^2 = 125<BR>\n" );
document.write( "w = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%28125%29 ALIGN=MIDDLE  ALT=\"sqrt%28125%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "w = 11.18 km/hr is the speed of the wind<BR>\n" );
document.write( ":<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Check this, find the actual time each way<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2825-11.2%29 ALIGN=MIDDLE  ALT=\"1%2825-11.2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = .0724 hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2825%2B11.2%29 ALIGN=MIDDLE  ALT=\"1%2825%2B11.2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = .0276 hrs<BR>\n" );
document.write( "------------------------------<BR>\n" );
document.write( "round trip time: = .1000 hrs<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );