document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=78342>Question 78342</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with this story problem.\r<BR>\n" );
document.write( "\n" );
document.write( "A post office sells first-class stamps and postcard stamps. For the year, the post office sold 7 first -class stamps for every 2 postcard stamps sold.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "a. the post office sold 46, 260 stamps for the year. How many of them were first-class stamps? how many were postcard stamps? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #56184 by </B><A HREF=/tutors/aboutme.mpl?userid=bucky><B>bucky(2189)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=bucky><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=56184\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Since the post office sells 7 first-class stamps for every 2 postcard stamps, this means<BR>\n" );
document.write( "that of every 9 stamps it sells, 7 are first-class.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Therefore the ratio of first-class stamps to total stamps is 7 to 9 or 7:9.  You are told<BR>\n" );
document.write( "that the total of the stamps sold in a year is 46,260.  With these figures we can now write<BR>\n" );
document.write( "a proportion:<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7%2F9+=+x%2F46260 ALIGN=MIDDLE  ALT=\"7%2F9+=+x%2F46260\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( "in which x represents the number of first-class stamps sold in a year.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "You can begin to solve proportions by cross-multiplying ... that is by multiplying the numerator<BR>\n" );
document.write( "of the left side times the denominator of the right side, multiplying the denominator<BR>\n" );
document.write( "of the left side times the numerator of the right side, and then setting the two products<BR>\n" );
document.write( "equal.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "These two multiplications are: 7*46260 and 9*x.  Setting them equal results in:<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9x+=+7%2846260%29 ALIGN=MIDDLE  ALT=\"9x+=+7%2846260%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( "Performing the multiplication on the right results in:<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9x+=+323820 ALIGN=MIDDLE  ALT=\"9x+=+323820\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( "Finally divide both sides by 9 to solve for x.  This is:<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+323820%2F9+=+35980 ALIGN=MIDDLE  ALT=\"x+=+323820%2F9+=+35980\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( "So you know that 35980 of the 46260 stamps were first-class.  Subtract 35980 from the<BR>\n" );
document.write( "46260 and you get that the number of postcard stamps sold in the year was:<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=46260+-+35980+=+10280 ALIGN=MIDDLE  ALT=\"46260+-+35980+=+10280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( "You can check this to see if the ratio of first-class stamps to postcard stamps is 7:2.<BR>\n" );
document.write( "In other words, does:<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=35980%2F10280 ALIGN=MIDDLE  ALT=\"35980%2F10280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( "give you the same ratio as <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7%2F2 ALIGN=MIDDLE  ALT=\"7%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( "Dividing 35980 by 10280 results in 3.5.  And dividing 7 by 2 also results in 3.5.<BR>\n" );
document.write( "The answer checks!<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Hope this gives you some insight into solving proportions.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );