document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1188058>Question 1188058</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me answer this question on grpah and algebraically :\r<BR>\n" );
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document.write( "You are comparing two mobile phone text plans that a phone company has to offer.\r<BR>\n" );
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document.write( "Plan A: uses formula y= 0.07x<BR>\n" );
document.write( "Plan B: uses formula y=0.02x+10\r<BR>\n" );
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document.write( "Where y is the monthly cost, in pounds and x is the number of texts sent or received per month. Draw the horizontal axis for x from 0 to 240 and the vertical axis for y from 0.25\r<BR>\n" );
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document.write( "a) Draw the graph of y=0.07x<BR>\n" );
document.write( "b) Draw the graph of y=0.02x+10\r<BR>\n" );
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document.write( "Use your graph to answer the following:\r<BR>\n" );
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document.write( "c) Which Plan is it cheaper to use if you were sending/receiving 10 texts per day?\r<BR>\n" );
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document.write( "d) Which Plan is it cheaper to use if you were sending/receiving 180 texts per month ?\r<BR>\n" );
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document.write( "e) for what number of texts do both plans make the same charge?    </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #819122 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=819122\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> here's my graph.\r<BR>\n" );
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document.write( "red is .07 pounds per text.<BR>\n" );
document.write( "blue is .02 pounds per text plus 10 pounds for the month.\r<BR>\n" );
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document.write( "from the graph, you can see that the plans break even when the user sends 200 texts per month.\r<BR>\n" );
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document.write( "when that occurs, the cost is 14 pounds for the month.\r<BR>\n" );
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document.write( "if the number of texts per month is greater than 200, then the .02 pounds per text + 10 pounds per month is cheaper.\r<BR>\n" );
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document.write( "on the graph, y is the total cost per month and x is the number of texts per month.\r<BR>\n" );
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document.write( "there are approximately 365/12 = 30.4 days in a month.\r<BR>\n" );
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document.write( "at 10 texts a day, you would be sending approximately 10 * that = 304 texts for the month.\r<BR>\n" );
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document.write( "at a cost of .07 per text, that would be equal to .07 * 304 = 21.28 pounds for the month.\r<BR>\n" );
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document.write( "at a cost of .02 per text + 10 pounds per month, that would be equal to .02 * 304 + 10 = 16.08 pounds for the month.\r<BR>\n" );
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document.write( "the .02x + 10 plan is cheaper at 304 texts per month.\r<BR>\n" );
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document.write( "if you are sending 180 texts per month, then:\r<BR>\n" );
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document.write( "at a cost of .07 per text, your cost for the month would be .07 * 180 = 12.6 pounds for the month.\r<BR>\n" );
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document.write( "at a cost of .02 per text + 10 pounds per month, your cost for the month would be .02 * 180 + 10 = 13.6 pounds for the month.\r<BR>\n" );
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document.write( "the .07 per text is cheaper at 180 texts per month.\r<BR>\n" );
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document.write( "at 10 texts per day, the .02 pounds per text + 10 pounds per month plan is cheaper.<BR>\n" );
document.write( "at 180 texts per month, the .07 pounds per text is cheaper.\r<BR>\n" );
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document.write( "the graph shows the following:\r<BR>\n" );
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document.write( "coordinate points on the graph are in (x,y) format.<BR>\n" );
document.write( "x is the number of text messages.<BR>\n" );
document.write( "y is the total cost in pounds.\r<BR>\n" );
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document.write( "the blue is the .07 pounds per text plan.<BR>\n" );
document.write( "the red is the .02 pounds per text plus 10 pounds per month plan.\r<BR>\n" );
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document.write( "at 10 texts per day, the number of texts per month is approximately 304.<BR>\n" );
document.write( "the .02 pounds per text plus 10 pounds per month is cheaper, because .07 * 304 = 21.28, while .02 * 304 + 10 = 16.08 pounds.\r<BR>\n" );
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document.write( "at 180 texts per month, the .07 pounds per text plan is cheaper, because .07 * 180 = 12.6, while .02 * 180 + 10 = 13.6.\r<BR>\n" );
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document.write( "both plans cost the same at 200 texts a month.\r<BR>\n" );
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document.write( "here's what the graph looks like.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" src = \"http://theo.x10hosting.com/2021/112101.jpg\" >\r<BR>\n" );
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document.write( "let me know if you have any questions.\r<BR>\n" );
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document.write( "theo </SPAN>\n" );
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