document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=163953>Question 163953</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780495565215/algebrahomeworkh>College Algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> A cell phone company charges a monthly fee of $10 for the first 1000 text messages and 10 cents for each additional text message. Miriam's bill for text messages for the month of June is $38.50. How many text messages did she send that month?<BR>\n" );
document.write( "I can figure out the answer(1285 messages) but I don't know how to write the formula.<BR>\n" );
document.write( "Thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #120802 by </B><A HREF=/tutors/aboutme.mpl?userid=gonzo><B>gonzo(654)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=gonzo><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=120802\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> total messages for the month is 3850 as follows:<BR>\n" );
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document.write( "let C = cost<BR>\n" );
document.write( "let M = number of messages greater than 1000<BR>\n" );
document.write( "formula is:<BR>\n" );
document.write( "C = $10 + $.01*M<BR>\n" );
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document.write( "substitute known values in equation.<BR>\n" );
document.write( "$38.50 = $10 + $.01*M<BR>\n" );
document.write( "subtract $10 from both sides of equation.<BR>\n" );
document.write( "$28.5 = $.01*M<BR>\n" );
document.write( "divide both sides of the equation by $.01.<BR>\n" );
document.write( "2850 = M<BR>\n" );
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document.write( "looks like number of messages greater than 1000 is 2850.<BR>\n" );
document.write( "to prove, substitute in original equation.<BR>\n" );
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document.write( "$38.50 = $10.00 + $.01*2850<BR>\n" );
document.write( "$38.50 = $10.00 + $28.50<BR>\n" );
document.write( "$38.50 = $38.50<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "the value of 2850 for M is good.<BR>\n" );
document.write( "total messages for the month would be 2850 + 1000 = 3850.<BR>\n" );
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document.write( "</TD></TR></TABLE>\n" );