document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=237580>Question 237580</A>: <I><SPAN STYLE=\"word-break: break-all;\"> if a:b = 4:5 and a:(b+c)= 3:7 then a:c is\r<BR>\n" );
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document.write( "a) 1:2 b) 2:5 c) 4:7  d) 12:13 e) 20:21\r<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 #174700 by </B><A HREF=/tutors/aboutme.mpl?userid=nyc_function><B>nyc_function(2741)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nyc_function><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=nyc_function><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=174700\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let a = 4\r<BR>\n" );
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document.write( "Let b = 5\r<BR>\n" );
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document.write( "Then we can make:\r<BR>\n" );
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document.write( "4/(5 + c) = 3/7\r<BR>\n" );
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document.write( "Cross-multiply:\r<BR>\n" );
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document.write( "3(5 + c) = 4(7)\r<BR>\n" );
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document.write( "15 + 3c = 28\r<BR>\n" );
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document.write( "3c = 28 - 15\r<BR>\n" );
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document.write( "3c = 13\r<BR>\n" );
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document.write( "c = 13/3\r<BR>\n" );
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document.write( "We are looking for a:c, which is really a/c.\r<BR>\n" );
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document.write( "We know a and we just found b.\r<BR>\n" );
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document.write( "So, plug and chug.\r<BR>\n" );
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document.write( "4/(13/3) = 12/13 = 12:13\r<BR>\n" );
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document.write( "Answer is choice d.\r<BR>\n" );
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document.write( "By the way, a:b can also be written a to c, which can also be written as a/c.\r<BR>\n" );
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document.write( "They all mean the same thing.\r<BR>\n" );
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document.write( "Think about it this way:\r<BR>\n" );
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document.write( "Batman:Robin = Batman to Robin = Batman/Robin\r<BR>\n" );
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