document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=991290>Question 991290</A>: <I><SPAN STYLE=\"word-break: break-all;\"> use proportions to solve\r<BR>\n" );
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document.write( "a transformer reduces or increases the voltage (V) of an alternating current based on the ratio of the coils in the input circuit (N in) to the coils in the output circuit (N out) according to the following proportion: V out/ V in = N out/ N in. A transformer is used to reduce the 120V household current to the 18V used in model train sets. If the transformer has 180 coils on the input circuit, how many coils are on the output circuit? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #611170 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=611170\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> VO / VI = NO / NI\r<BR>\n" );
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document.write( "VO = voltage out<BR>\n" );
document.write( "VI = voltage in<BR>\n" );
document.write( "NO = number of coils out<BR>\n" );
document.write( "NI = number of coils in\r<BR>\n" );
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document.write( "VI = 120 volts<BR>\n" );
document.write( "VO = 18 volts\r<BR>\n" );
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document.write( "NI = 180<BR>\n" );
document.write( "NO = x\r<BR>\n" );
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document.write( "x = the number of coils out.\r<BR>\n" );
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document.write( "you want to solve for x.\r<BR>\n" );
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document.write( "VO / VI = NO / NI becomes 18 / 120 = x / 180\r<BR>\n" );
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document.write( "cross multiply to get 18 * 180 = 120 * x\r<BR>\n" );
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document.write( "divide both sides of the equation by 120 to get 18 * 180 / 120 = x\r<BR>\n" );
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document.write( "solve for x to get x = 27.\r<BR>\n" );
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document.write( "number of coils out needs to be equal to 27.\r<BR>\n" );
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document.write( "you get:\r<BR>\n" );
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document.write( "VI = 120<BR>\n" );
document.write( "VO = 18<BR>\n" );
document.write( "NI = 180<BR>\n" );
document.write( "NO = 27\r<BR>\n" );
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document.write( "VO / VI = NO / NI becomes 18 / 120 = 27 / 180\r<BR>\n" );
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document.write( "simplify to get .15 = .15 which is true, confirming the solution is correct.\r<BR>\n" );
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document.write( "the solution is that the number of coils on the output circuit are equal to 27.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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