document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1113018>Question 1113018</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How many bit strings of length 4 contain either 3 consecutive 0s or 3 consecutive 1s?<BR>\n" );
document.write( "Select one:<BR>\n" );
document.write( "a. 4<BR>\n" );
document.write( "b. 7<BR>\n" );
document.write( "c. 5<BR>\n" );
document.write( "d. 6 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #728072 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13203)</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=728072\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "What don't you understand about this problem...?<br><BR>\n" );
document.write( "A bit string contains only digits 0 or 1; if a bit string is of length 4, then the total number of different bit strings is 2*2*2*2 = 16.  It isn't a lot of work to write out all 16 of those strings and find the ones that have either 3 consecutive 0s or 3 consecutive 1s.<br><BR>\n" );
document.write( "Or you could do just a little basic logical analysis.  If a bit string of length 4 has 3 consecutive 0s, what are the possibilities?  And likewise if it has 3 consecutive 1s?<br><BR>\n" );
document.write( "And remember that the problem doesn't say EXACTLY 3 consecutive 0s or 1s.  The two strings 0000 and 1111 both contain 3 consecutive 0s or 3 consecutive 1s.      </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );