document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1010408>Question 1010408</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The electric power P varies jointly as the resistance R and the square of the current I. If<BR>\n" );
document.write( "the power is 40 watts when the resistance is 10 ohms and the current is 1.33 amps, what is<BR>\n" );
document.write( "the power when the current is 5 amps and the resistance is 25 ohms? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #625827 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=625827\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> direct variation formula is y = kx\r<BR>\n" );
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document.write( "inverse variation formula is y = k/x\r<BR>\n" );
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document.write( "joint variation formula is y = kxz\r<BR>\n" );
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document.write( "k = constant of variation.\r<BR>\n" );
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document.write( "it remains the same in each equation regardless of the values of the other variables in that equation.\r<BR>\n" );
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document.write( "in your problem:\r<BR>\n" );
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document.write( "y = p<BR>\n" );
document.write( "x = r<BR>\n" );
document.write( "z = i^2<BR>\n" );
document.write( "k = constant of variation\r<BR>\n" );
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document.write( "p = power<BR>\n" );
document.write( "r = resistance<BR>\n" );
document.write( "i = current\r<BR>\n" );
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document.write( "the formula of y = kxz becomes p = kri^2\r<BR>\n" );
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document.write( "when p = 40 and r = 10 and i = 1.33, the formula of p = kri^2 becomes <BR>\n" );
document.write( "40 = k*10*1.33^2\r<BR>\n" );
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document.write( "solve for k to get k = 40/(10*1.33^2) which becomes k = 2.261292329.\r<BR>\n" );
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document.write( "when r = 25 and i = 5, the formula of p = kri^2 becomes:\r<BR>\n" );
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document.write( "p = 2.261292329 * 25 * 5^2.\r<BR>\n" );
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document.write( "the value of k remains the same as it was when initially calculated.\r<BR>\n" );
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document.write( "solve for p to get p = 1413.307705.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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