document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1144193>Question 1144193</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The monthly cost (in dollars) of a long-distance phone plan is a linear function of the total calling time (in minutes). The monthly cost for 37\r<BR>\n" );
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document.write( " minutes of calls is $15.42\r<BR>\n" );
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document.write( " and the monthly cost for 53\r<BR>\n" );
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document.write( " minutes is $17.18\r<BR>\n" );
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document.write( ". What is the monthly cost for 39\r<BR>\n" );
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document.write( " minutes of calls? <BR>\n" );
document.write( "   <BR>\n" );
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document.write( "The additional 53-37 = 16 minutes cost an additional $17.18-$15.42 = $1.76; the rate is $1.76/16 = $0.11 per minute.<br><BR>\n" );
document.write( "The cost of 39 minutes of calls is the cost of 37 minutes of calls plus the cost of 2 more minutes at the rate of $0.11 per minute:<br><BR>\n" );
document.write( "$15.42 + 2($0.11) = $15.42 + $0.22 = $15.64 </SPAN>\n" );
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