document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=644246>Question 644246</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If a girl works for 8 min. and her brother works for 15 min, they can wash the front windows of their house. Also, if the girl works for 12 min and her brother works for 10 min, they can wash the same windows. How long will it take each person alone to wash the windows? (Hint: If it takes t minutes for a person to do a job alone, then in 1 min, the person can do 1/t of the job). </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #404906 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=404906\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If a girl works for 8 min. and her brother works for 15 min, they can wash the front windows of their house. Also, if the girl works for 12 min and her brother works for 10 min, they can wash the same windows. How long will it take each person alone to wash the windows? (Hint: If it takes t minutes for a person to do a job alone, then in 1 min, the person can do 1/t of the job).<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Let the girl's rate be \"g\" and the brother's rate be \"b\".<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "8g + 15b = 1 job<BR>\n" );
document.write( "12g+ 10b = 1 job<BR>\n" );
document.write( "---------------------<BR>\n" );
document.write( "80g + 150b = 10<BR>\n" );
document.write( "180g + 150b = 15<BR>\n" );
document.write( "----<BR>\n" );
document.write( "100g = 5<BR>\n" );
document.write( "g = 1/20 (girl's rate)<BR>\n" );
document.write( "1/g = 20 minutes (time for the girl to do the job alone)<BR>\n" );
document.write( "------<BR>\n" );
document.write( "Solve for \"b\":<BR>\n" );
document.write( "80(1/20) + 150b = 10<BR>\n" );
document.write( "150b = 6<BR>\n" );
document.write( "b = 1/25<BR>\n" );
document.write( "1/b = 25 minutes (time for the brother to do the job alone)<BR>\n" );
document.write( "==============<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );