document.write( "Question 1189433: What is the probability that a random arrangement of the letters in the word `SEVEN' will have both E's next to each other?
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #820791 by math_tutor2020(3817)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "Edit: I corrected the final answer to have it fully reduced. I appreciate @greenestamps pointing out the error.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "If we could tell the two \"E\"s apart, then there would be 5! = 5*4*3*2*1 = 120 permutations of the word SEVEN since there are 5 letters.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "However, we cannot tell the \"E\"s apart. This means we've double-counted when computing that figure of 120. So we must cut that figure in half to get 60.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "There are 60 ways to arrange the letters of SEVEN where the \"E\"s may or may not be together.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Let's take the \"E\"s out and replace it with some other letter. I'll use W.
\n" ); document.write( "So we go from the word SEVEN to the \"word\" SWVN\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "There are 4 distinct letters here, so there are 4! = 4*3*2*1 = 24 permutations. Anywhere you see a W, replace it with EE\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A permutation like WSVN is really EESVN
\n" ); document.write( "A permutation like SVWN is really SVEEN
\n" ); document.write( "and so on.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "--------------------------------------\r
\n" ); document.write( "\n" ); document.write( "We found that there are:
  • 24 ways to arrange the letters so the \"E\"s are together
  • 60 ways to arrange the letters overall
Divide the two values to get: 24/60 = (12*2)/(12*5) = 2/5\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Answer: 2/5
\n" ); document.write( "
\n" ); document.write( "
\n" );