document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1209628>Question 1209628</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me answer this question\r<BR>\n" );
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document.write( "The cost of petrol rises by 2cents a litre.<BR>\n" );
document.write( "Last week a man bought 20 litres at the old price<BR>\n" );
document.write( "This week he bought 10 litres at the new price<BR>\n" );
document.write( "All together it costed $9.20<BR>\n" );
document.write( "What was the old price for 1 litre<BR>\n" );
document.write( "Let x be the old price\r<BR>\n" );
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document.write( "Solution\r<BR>\n" );
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document.write( "I tried saying 20 times x plus 10 times x plus two is equal to 920cents<BR>\n" );
document.write( "Then I got 20x plus 10x plus 20 is equal to 920 cents <BR>\n" );
document.write( "Then I said 10x plus 20x is equal to 30x = 920 cents minus 20<BR>\n" );
document.write( "Then I sais 30x + 900 divided by 30\r<BR>\n" );
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document.write( "I then got the answer x = 0,30 cents<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 #849709 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52781)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><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=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=849709\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .<BR>\n" );
document.write( "Please help me answer this question\r<BR>\n" );
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document.write( "The cost of petrol rises by 2cents a litre.<BR>\n" );
document.write( "Last week a man bought 20 litres at the old price<BR>\n" );
document.write( "This week he bought 10 litres at the new price<BR>\n" );
document.write( "All together it costed $9.20<BR>\n" );
document.write( "What was the old price for 1 litre<BR>\n" );
document.write( "Let x be the old price\r<BR>\n" );
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document.write( "Solution\r<BR>\n" );
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document.write( "I tried saying 20 times x plus 10 times x plus two is equal to 920cents<BR>\n" );
document.write( "Then I got 20x plus 10x plus 20 is equal to 920 cents <BR>\n" );
document.write( "Then I said 10x plus 20x is equal to 30x = 920 cents minus 20<BR>\n" );
document.write( "Then I sais 30x + 900 divided by 30\r<BR>\n" );
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document.write( "I then got the answer x = 0,30 cents<BR>\n" );
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document.write( "Let x be the old price per liter (x dollars per liter).\r\n" );
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document.write( "Then the new price is (x + 0.02) dollars per liter.\r\n" );
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document.write( "Write an equation as you read the problem\r\n" );
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document.write( "    20x + 10*(x+0.02) = 9.20  dollars.\r\n" );
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document.write( "Simplify and find x\r\n" );
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document.write( "    20x + 10x + 0.20 = 9.20\r\n" );
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document.write( "        30x          = 9.20 - 0.20\r\n" );
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document.write( "        30x          =    9.00\r\n" );
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document.write( "          x          =    9.00/30\r\n" );
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document.write( "          x          =    0.30\r\n" );
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document.write( "<U>ANSWER</U>.  The old price was 0.30 dollars per liter.\r\n" );
document.write( "</PRE>\r<BR>\n" );
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document.write( "Solved.\r<BR>\n" );
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document.write( "The other person uses practically the same method of creating system of equations,<BR>\n" );
document.write( "as people do it for centuries, but introduces his own name for it as \"weighted average approach\".\r<BR>\n" );
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document.write( "As far as I know, nobody and nowhere uses this term in solving/treating such problems when teaching.\r<BR>\n" );
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document.write( "In addition, this terminology \"weighted average approach\" is factually incorrect/irrelevant,<BR>\n" );
document.write( "since in this consideration, there is no weighted average, at all: there is weighted sum, instead.\r<BR>\n" );
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document.write( "So, I do not see any reason for a reader to learn from this author,<BR>\n" );
document.write( "stumbling over unnecessary and incorrect terminology that the author introduces without any need.\r<BR>\n" );
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document.write( "I'd advise to a reader to avoid such tutors and/or teachers, who earn their popularity <BR>\n" );
document.write( "by introducing their own terms for well known methods and conceptions,<BR>\n" );
document.write( "and then sell it as their innovations. It is a form of deceiving readers.\r<BR>\n" );
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document.write( "In addition, he uses unreadable format - to convince a reader that he is so much original ?\r<BR>\n" );
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document.write( "Web-site, which this person gives for contacts, does not work.\r<BR>\n" );
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document.write( "In short, total and fatal absurd.\r<BR>\n" );
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