document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1190592>Question 1190592</A>: <I><SPAN STYLE=\"word-break: break-all;\"> on monday, revlien paid 66 pesos for 3 doughnuts and 2 cups of coffee. on tuesday, she paid 69 pesos for 2 doughnuts and 3 cups of coffee. how much did he pay for 1 doughnut and 1 cup of coffee on a wednesday?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #822299 by </B><A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><B>math_tutor2020(3817)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><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=822299\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "d = cost of 1 doughnut<BR>\n" );
document.write( "c = cost of 1 coffee<BR>\n" );
document.write( "costs are in pesos\r<BR>\n" );
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document.write( "Setting up the cost for Monday<BR>\n" );
document.write( "3d = cost of 3 doughnuts<BR>\n" );
document.write( "2c = cost of 2 coffees<BR>\n" );
document.write( "3d+2c = total cost of the 5 items overall<BR>\n" );
document.write( "3d+2c = 66 pesos\r<BR>\n" );
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document.write( "Let's solve for c<BR>\n" );
document.write( "3d+2c = 66<BR>\n" );
document.write( "2c = 66-3d<BR>\n" );
document.write( "c = (66-3d)/2<BR>\n" );
document.write( "c = (66/2)-(3d/2)<BR>\n" );
document.write( "c = 33 - 1.5d<BR>\n" );
document.write( "I'll use this later on.\r<BR>\n" );
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document.write( "Setting up the cost for Tuesday<BR>\n" );
document.write( "2d = cost of 2 doughnuts<BR>\n" );
document.write( "3c = cost of 3 coffees<BR>\n" );
document.write( "2d+3c = total cost of these 5 new items<BR>\n" );
document.write( "2d+3c = 69 pesos\r<BR>\n" );
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document.write( "Apply substitution<BR>\n" );
document.write( "2d+3c = 69<BR>\n" );
document.write( "2d+3( c ) = 69<BR>\n" );
document.write( "2d+3( 33-1.5d ) = 69 ... c replaced with 33-1.5d<BR>\n" );
document.write( "2d+99-4.5d = 69<BR>\n" );
document.write( "-2.5d = 69-99<BR>\n" );
document.write( "-2.5d = -30<BR>\n" );
document.write( "d = -30/(-2.5)<BR>\n" );
document.write( "d = 12<BR>\n" );
document.write( "It costs 12 pesos for 1 doughnut\r<BR>\n" );
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document.write( "c = 33 - 1.5d<BR>\n" );
document.write( "c = 33 - 1.5(12)<BR>\n" );
document.write( "c = 33 - 18<BR>\n" );
document.write( "c = 15<BR>\n" );
document.write( "It costs 15 pesos for 1 coffee\r<BR>\n" );
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document.write( "Check for Monday:<BR>\n" );
document.write( "3d+2c = 66<BR>\n" );
document.write( "3*12+2*15 = 66<BR>\n" );
document.write( "36+30 = 66<BR>\n" );
document.write( "66 = 66 that works out\r<BR>\n" );
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document.write( "Check for Tuesday:<BR>\n" );
document.write( "2d+3c = 69<BR>\n" );
document.write( "2*12+3*15 = 69<BR>\n" );
document.write( "24+45 = 69<BR>\n" );
document.write( "69 = 69 that works out as well\r<BR>\n" );
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document.write( "We've confirmed we have the correct unit prices for each food item.\r<BR>\n" );
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document.write( "For Wednesday, she bought 1 doughnut and 1 coffee<BR>\n" );
document.write( "So the amount paid is d+c = 12+15 = 27 pesos<BR>\n" );
document.write( "This excludes any kind of tax or extra surcharges.\r<BR>\n" );
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document.write( "Answer: 27 pesos<BR>\n" );
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