document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=956681>Question 956681</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A man bought 42 stamps, some 13¢ and some 18¢. How many of each kind did he buy if the cost was $6.66? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #584493 by </B><A HREF=/tutors/aboutme.mpl?userid=addingup><B>addingup(3677)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=addingup><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=addingup><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=584493\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let's call the 13¢ stamps a and the 18¢ stamps b:<BR>\n" );
document.write( "a+b = 42 and therefore a= 42-b (formula 1)<BR>\n" );
document.write( "0.13a+0.18b= 6.66 In this formula, substitute the value of a according to formula 1:<BR>\n" );
document.write( "0.13(42-b)+0.18b= 6.66 Multiply on the left to get rid of the parenthesis:<BR>\n" );
document.write( "5.46-0.13b+0.18b= 6.66 Subtract 5.46 from both sides:<BR>\n" );
document.write( "-0.13b+0.18b= 1.20 Add on the left:<BR>\n" );
document.write( "0.05b= 1.20 Divide both sides by 0.05<BR>\n" );
document.write( "b= 24 You have 24 18¢ stamps and:<BR>\n" );
document.write( "42-24= 18 13¢ stamps<BR>\n" );
document.write( "Check: (24 x 0.18) + (18 x 0.13)= 6.66 Correct.<BR>\n" );
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