document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=502465>Question 502465</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the number of four-letter strings of the alphabet, repetitions allowed, that contain at least one \"G\" AND at least one \"T.\"  I know that those containing at least one \"G\" is 26^4-25^4, and those containing at least one \"T\" is 26^4-25^4. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #339050 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=339050\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <BR>\n" );
document.write( " number of 4 - letter strings that don't contain G = 24^4\r<BR>\n" );
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document.write( " number of 4 - letter strings that don't contain T = 24^4\r<BR>\n" );
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document.write( " number of 4- letter strings that don't contain neither G nor T = 24^4 <BR>\n" );
document.write( "    \r<BR>\n" );
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document.write( " number of four-letter strings of the alphabet, that contain at least one \"G\" AND\r<BR>\n" );
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document.write( " at least one \"T.\" = 26^4 - ( 25^4 + 25^4 - 24^4)\r<BR>\n" );
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document.write( "  \r<BR>\n" );
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document.write( "if any doubt, you are welcome to contact.<BR>\n" );
document.write( " </SPAN>\n" );
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