document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=105609>Question 105609</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A purse containing $3.20 in quarters and dimes has, in all, 20 coins.  Find the number of each kind of coin. \r<BR>\n" );
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document.write( "(i need help!!!) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #76864 by </B><A HREF=/tutors/aboutme.mpl?userid=doukungfoo><B>doukungfoo(195)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=doukungfoo><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=doukungfoo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=76864\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> lets call the number of quarters x<BR>\n" );
document.write( "and the number of dimes y<BR>\n" );
document.write( "number of quarters = x<BR>\n" );
document.write( "number of dimes = y<BR>\n" );
document.write( "Given: there are a total of 20 coins<BR>\n" );
document.write( "x + y = 20<BR>\n" );
document.write( "Given: the value of all coins is $3.20<BR>\n" );
document.write( "Known: a dime is worth .10 cents<BR>\n" );
document.write( "and a quarter is worth .25 cents<BR>\n" );
document.write( ".25x + .10y = $3.20<BR>\n" );
document.write( "In other words, .25 times the number of quarters (x) plus .10 times the number of dimes (y) equals $3.20<BR>\n" );
document.write( "So now we have a system of equations that we can use to solve for x and y<BR>\n" );
document.write( "x + y = 20<BR>\n" );
document.write( "AND <BR>\n" );
document.write( ".25x + .10y = 3.20<BR>\n" );
document.write( "Start with the first equation and set it equal to x<BR>\n" );
document.write( "x + y = 20<BR>\n" );
document.write( "x = 20 - y<BR>\n" );
document.write( "Now since we have shown that x equals 20-y we can substitute the x in the second equation with 20-y and solve for y<BR>\n" );
document.write( ".25x + .10y = 3.20<BR>\n" );
document.write( ".25(20-y) + .10y = 3.20<BR>\n" );
document.write( "5 - .25y + .10y = 3.20<BR>\n" );
document.write( "5 - .15y = 3.20<BR>\n" );
document.write( "-.15y = -1.80<BR>\n" );
document.write( "y = 12<BR>\n" );
document.write( "<b>Answer: The purse contains 12 dimes</B><BR>\n" );
document.write( "Now we can use this to solve for x<BR>\n" );
document.write( "x + y = 20<BR>\n" );
document.write( "x + 12 = 20<BR>\n" );
document.write( "x = 8<BR>\n" );
document.write( "<b>Answer: The purse contains 8 quarters</B><BR>\n" );
document.write( "Check answers by trying them in both equations<BR>\n" );
document.write( "x + y = 20<BR>\n" );
document.write( "8 + 12 = 20<BR>\n" );
document.write( "20 = 20<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( ".25x + .10y = 3.20<BR>\n" );
document.write( ".25(8) + .10(12) = 3.20<BR>\n" );
document.write( "2 + 1.20 = 3.20<BR>\n" );
document.write( "3.20 = 3.20\r<BR>\n" );
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document.write( " </SPAN>\n" );
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