document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=13602>Question 13602</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Here is the queston:<BR>\n" );
document.write( "how do I set up the equation?<BR>\n" );
document.write( "A collection of coins is worth $7.50. There are nickles, dimes and quarters with twice as many dimes as there are nickles. Altogether there are 70 coins. how many nickles, dines, and quarters are in the collection? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #6847 by </B><A HREF=/tutors/aboutme.mpl?userid=LilSkittleMd><B>LilSkittleMd(119)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=LilSkittleMd><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=6847\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> For this problem you have 3 equations. They are:<BR>\n" );
document.write( "n+d+q=70 <BR>\n" );
document.write( "(since there are 70 coins altogether, the number of each coin will add up to 70)<BR>\n" );
document.write( "d=2n<BR>\n" );
document.write( "(there are twice as many dimes as there are nickels)<BR>\n" );
document.write( "0.05n+0.10d+0.25q=7.50<BR>\n" );
document.write( "(the amount of how much each coin is worth, multiplied by the number of the coin is equal to $7.50)<BR>\n" );
document.write( "The first step is to eliminate one variable from two equations. Using the elimination method seems to be the easiest (add the two equations together, eliminating one variable)<BR>\n" );
document.write( "Take the first and last equation. Multiply the first equation by -0.25 to cancel out the variable q.<BR>\n" );
document.write( " -0.25n-0.25d-0.25q=-17.5<BR>\n" );
document.write( "+ 0.05n+0.10d+0.25q=7.50 (Add the two equations to come up with an equation without the variable q)<BR>\n" );
document.write( "-0.2n-0.15d=-10<BR>\n" );
document.write( "Take the d=n equation and plug it into the new equation:<BR>\n" );
document.write( "-0.2n-0.15(2n)=-10 (Solve the equation)<BR>\n" );
document.write( "-0.2n-0.3n=-10<BR>\n" );
document.write( "-0.5n=-10 (divide each side of the equation by -0.5)<BR>\n" );
document.write( "n=20<BR>\n" );
document.write( "Now place the value of n into an equation:<BR>\n" );
document.write( "d=2(20)<BR>\n" );
document.write( "d=40<BR>\n" );
document.write( "Now place these 2 variables into an equation with all three variables:<BR>\n" );
document.write( "20+40+q=70 (Solve this equation)<BR>\n" );
document.write( "60+q=70<BR>\n" );
document.write( "q=10<BR>\n" );
document.write( "There are 20 nickels, 40 dimes, and 10 quarters in the collection.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );