document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1154401>Question 1154401</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The math department bought some calculators for a total of $240 . The department head kept one for the math office and then sold the rest for 300 making a profit of $ 5 on each calculator . How many calculators did the math department buy ? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #776833 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=776833\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Tutor @ikleyn has provided a perfectly good algebraic solution; here is a very different approach....<br><BR>\n" );
document.write( "The math department bought n calculators for d dollars each, for a cost of $240:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=nd+=+240 ALIGN=MIDDLE  ALT=\"nd+=+240\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "They sold (n-1) calculators for (d+5) dollars each, for a total of $300:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28n-1%29%28d%2B5%29+=+300 ALIGN=MIDDLE  ALT=\"%28n-1%29%28d%2B5%29+=+300\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=nd-d%2B5n-5+=+300 ALIGN=MIDDLE  ALT=\"nd-d%2B5n-5+=+300\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=240-d%2B5n-5+=+300 ALIGN=MIDDLE  ALT=\"240-d%2B5n-5+=+300\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d+=+5n-65 ALIGN=MIDDLE  ALT=\"d+=+5n-65\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%285n-65%29+=+240 ALIGN=MIDDLE  ALT=\"n%285n-65%29+=+240\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%28n-13%29+=+48 ALIGN=MIDDLE  ALT=\"n%28n-13%29+=+48\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%5E2-13n-48+=+0 ALIGN=MIDDLE  ALT=\"n%5E2-13n-48+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28n-16%29%28n%2B3%29+=+0 ALIGN=MIDDLE  ALT=\"%28n-16%29%28n%2B3%29+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n+=+16 ALIGN=MIDDLE  ALT=\"n+=+16\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n+=+-3 ALIGN=MIDDLE  ALT=\"n+=+-3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Obviously the negative answer makes no sense.  So the number of calculators the math department bought was 16.<br><BR>\n" );
document.write( "CHECK:<BR>\n" );
document.write( "16 calculators for $240 means $15 each.<BR>\n" );
document.write( "16-1 = 15 calculators for $15+$5 = $20 each makes $300.<br><BR>\n" );
document.write( " </SPAN>\n" );
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