document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=445640>Question 445640</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 18. Suppose the code to a lock consists of there different numbers from the numbers 1 to 20, inclusive.\r<BR>\n" );
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document.write( "a. How many three-number codes are possible?\r<BR>\n" );
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document.write( "b. How many of the codes contain the numbers 6,13, and 17?\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 #307211 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><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=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=307211\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a: Assuming order matters, the number of ways is 20P3 = 20*19*18.\r<BR>\n" );
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document.write( "b: There are 3! = 6 ways to arrange 6, 13, 17 to form different codes (e.g. 6-13-17 is different from 13-17-6, etc.) </SPAN>\n" );
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