document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=260497>Question 260497</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a disc jockey must play 12 commercial spots during a 1 hour of radio.each commercial spot is either 30 seconds or 60 seconds. if the total commercial time is 1 hour 8 minutes, how many 30 second commercials are there? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #191872 by </B><A HREF=/tutors/aboutme.mpl?userid=drk><B>drk(1908)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=drk><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=191872\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let X = 30 sec and Y = 60 sec spots. Now 1 hr 8 min - 1 hr = 8 min = 480 seconds.<BR>\n" );
document.write( "we get<BR>\n" );
document.write( "(i) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X+%2B+Y+=+12 ALIGN=MIDDLE  ALT=\"X+%2B+Y+=+12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(ii) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30X+%2B+60Y+=+480 ALIGN=MIDDLE  ALT=\"30X+%2B+60Y+=+480\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "step 1 - solve (i) for X to get<BR>\n" );
document.write( "(iii) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+X+=+12+-+Y ALIGN=MIDDLE  ALT=\"+X+=+12+-+Y\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "substitute (iii) into (ii) to get<BR>\n" );
document.write( "(iv) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30%2812-Y%29+%2B+60Y+=+480 ALIGN=MIDDLE  ALT=\"30%2812-Y%29+%2B+60Y+=+480\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "distribute to get<BR>\n" );
document.write( "(v) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360+-+30Y+%2B+60Y+=+480 ALIGN=MIDDLE  ALT=\"360+-+30Y+%2B+60Y+=+480\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "combine like terms to get<BR>\n" );
document.write( "(vi) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30Y+=+120 ALIGN=MIDDLE  ALT=\"30Y+=+120\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Y = 4<BR>\n" );
document.write( "X = 8<BR>\n" );
document.write( "There are 8 - 30 second comercials<BR>\n" );
document.write( "  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );