document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=389350>Question 389350</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Bart has two choices to make a long distance phone call.  His two choices are:10-10-220 and AT&T.  Using 10-10-220, the cost is 99 cents for the first twenty minutes, and 7 cents for each additional minute.  AT&T just charges 6 cents for each minute.  After how many total minutes will it be less expensive to use AT&T?  Assume the call is at least 20 minutes. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #275883 by </B><A HREF=/tutors/aboutme.mpl?userid=robertb><B>robertb(5830)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=robertb><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=robertb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=275883\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let m = # minutes of call.  By assumption, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m+%3E=+20 ALIGN=MIDDLE  ALT=\"m+%3E=+20\"   DISABLED_style= \"max-width:90%; height:auto;\" >.  Then we have to solve the equation<BR>\n" );
document.write( "0.99 + (m - 20)0.07 = 0.06m,<BR>\n" );
document.write( "0.99 + 0.07m - 1.4 = 0.06m,<BR>\n" );
document.write( "-0.41 = -0.01m,<BR>\n" );
document.write( "m = 41, total # minutes after which it be less expensive to use AT&T </SPAN>\n" );
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