document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=484339>Question 484339</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 1) A telephone number consists of seven digits. How many different telephone numbers exist if each digit appears only one time in the number? How would I solve this type of problem?\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 #331932 by </B><A HREF=/tutors/aboutme.mpl?userid=sudhanshu_kmr><B>sudhanshu_kmr(1152)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=sudhanshu_kmr><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=sudhanshu_kmr><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=331932\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <BR>\n" );
document.write( "For first digit, we can use any one of 9 digits, except 0 i.e (1,2,3,...9)\r<BR>\n" );
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document.write( "for second digit, we can use any one of  : 9 (except which is on first position)\r<BR>\n" );
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document.write( "similarly, for third digit, we can use any one of  : 8 (except first and second)\r<BR>\n" );
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document.write( "and so on......\r<BR>\n" );
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document.write( "number of possible numbers = 9*9*8*7*6*5*4 = 544320\r<BR>\n" );
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