document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1163782>Question 1163782</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Every cereal box has a gift inside, but you cannot tell from the outside what the gift is. The store manager assures you that 18 of the 52 boxes on the shelf have the secret decoder ring. The other 34 boxes on the shelf have a different gift inside. If you randomly select two boxes of cereal from the shelf to purchase, what is the probability that BOTH of them have the secret decoder ring?\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #787987 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=787987\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "P(first box has a decoder ring) = 18/52<br><BR>\n" );
document.write( "P(second box has a decoder ring) = 17/51<br><BR>\n" );
document.write( "P(both have decoder rings) = (18/52)*(17/51) = (9/26)(1/3) = 3/26<br><BR>\n" );
document.write( "OR....<br><BR>\n" );
document.write( "Using a more sophisticated method -- which might be required in similar but more complicated problems....<br><BR>\n" );
document.write( "P(both have decoder rings) = (# of ways of choosing 2 of the 18 boxes with decoder rings) divided by (# of ways of choosing 2 of the 52 boxes)<br><BR>\n" );
document.write( " = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C%2818%2C2%29%2FC%2852%2C2%29+=+%28%2818%2A17%29%2F%282%2A1%29%29%2F%28%2852%2A51%29%2F%282%2A1%29%29+=+%2818%2A17%29%2F%2852%2A51%29+=+%2818%2F52%29%2817%2F51%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "which is the same calculation as by the more elementary method.<br><BR>\n" );
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