document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1055488>Question 1055488</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A technician can assemble an instrument in 9.5 h . After working for 2.0 h , she is joined by another technician who, alone, could do the job in 7.5 h . How many additional hours are needed to finish 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 #670696 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=670696\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The work rate of technician is 1 instrument per 9.5 h, or r1 = 1/9.5 = 2/19<BR>\n" );
document.write( "The work rate of her assistant is 1 instrument per 7.5 h, or r2 = 1/7.5 = 2/15<BR>\n" );
document.write( "The technician working for 2 hours alone has completed (2/19)*2 = 4/19 of the instrument.<BR>\n" );
document.write( "Therefore, 15/19 remains to be completed.<BR>\n" );
document.write( "Working together, their combined rate, r, is 2/19 + 2/15 = 30/285 + 38/285 = 68/285 instruments per hour.<BR>\n" );
document.write( "They need to complete 15/19, or 225/285 instruments.<BR>\n" );
document.write( "So r*t = 225/285<BR>\n" );
document.write( "t = 225/285*285/68 = 225/68 = 3.31 hours<BR>\n" );
document.write( " </SPAN>\n" );
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