document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1048809>Question 1048809</A>: <I><SPAN STYLE=\"word-break: break-all;\"> On MOnday, Harold picked up six donuts and 2 large coffees for the office staff. He paid $5.74. On Tuesday, Melinda picked up 3 donuts and 5 large coffee for the office staff. She paid $7.17. what is the cost of 1 donut? What is the cost of 1 large coffee? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #664378 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=664378\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> d = number of donuts.<BR>\n" );
document.write( "c = number of large coffee.\r<BR>\n" );
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document.write( "your equations are.\r<BR>\n" );
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document.write( "6d + 2c = 5.74<BR>\n" );
document.write( "3d + 5c = 7.17\r<BR>\n" );
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document.write( "multiply both sides of the second equation by 2 to get and leave the first equation alone to get:\r<BR>\n" );
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document.write( "6d + 2c = 5.74<BR>\n" );
document.write( "6d + 10c = 14.34\r<BR>\n" );
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document.write( "subtract the first equation from the second to get:\r<BR>\n" );
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document.write( "8c = 8.60\r<BR>\n" );
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document.write( "divide both sides of this equation by 2 to get:\r<BR>\n" );
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document.write( "c = 1.075\r<BR>\n" );
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document.write( "replace c with 1.075 in the first eqution and solve for d.\r<BR>\n" );
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document.write( "start with 6d + 2c = 5.74<BR>\n" );
document.write( "replace c with 1.075 to get 6d + 2 * 1.075 = 5.74<BR>\n" );
document.write( "simplify to get 6d + 2.15 = 5.74<BR>\n" );
document.write( "solve for d to get d = (5.74 - 2.15) / 6<BR>\n" );
document.write( "this makes d = .59833333.....\r<BR>\n" );
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document.write( "you have:\r<BR>\n" );
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document.write( "c = 1.075<BR>\n" );
document.write( "d = .59833333.....\r<BR>\n" );
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document.write( "replace c and d in both equations to see if both equations hold true.\r<BR>\n" );
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document.write( "first equation becomes 6d + 2c = 5.74 which becomes 6 * .59833333..... + 2 * 1.075 = 5.74 which becomes 5.74 = 5.74 which confirms the first equation is true.\r<BR>\n" );
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document.write( "second equation becomes 3d + 5c = 7.17 which becomes 3 * .59833333..... + 5 * 1.075 = 7.17 which becomes 7.17 = 7.17 which confirms the second equation is true.\r<BR>\n" );
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document.write( "both equations are true when c = .59833333..... and d = 1.075 so the solution looks good.\r<BR>\n" );
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document.write( "in my opinion, this problem is not very realistic.\r<BR>\n" );
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document.write( "i've never see a cup of coffee cost a fraction of a penny and i've never seen a donut cost a fraction of a penny.\r<BR>\n" );
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document.write( "despite that, the mathematics works out and that's your solution.\r<BR>\n" );
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document.write( "it's possible you copied the numbers wrong.<BR>\n" );
document.write( "if so, then duplicate the solution method using the right numbers and you should be ok.\r<BR>\n" );
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document.write( "  </SPAN>\n" );
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