document.write( "Question 1149532: Of the seven-letter words that can be formed without repetition from the letters of the word INCLUDE
\n" ); document.write( "how many have the letters N and D separated by more than two letters?
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Algebra.Com's Answer #770885 by greenestamps(13198)\"\" \"About 
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\n" ); document.write( "I will assume this question is from the same student that asked the number of words when the letters N and D are separated by EXACTLY two letters....

\n" ); document.write( "Then, continuing in the same manner as in my response to that question....

\n" ); document.write( "(1) N and D separated by THREE letters: (3)(2)(120) = 720
\n" ); document.write( "(2) N and D separated by FOUR letters: (2)(2)(120) = 480
\n" ); document.write( "(3) N and D separated by FIVE letters (the maximum): (1)(2)(120) = 240

\n" ); document.write( "ANSWER: 1440

\n" ); document.write( "Notice we can see that this method of counting the numbers of words with different numbers of letters between N and D is valid by finding the numbers of words for ALL the possible distances between N and D and showing that the sum is 7! =5040.

\n" ); document.write( "N and D separated by ONE letter: (5)(2)(120) = 1200
\n" ); document.write( "N and D separated by ZERO letters: (6)(2)(120) = 1440

\n" ); document.write( "That, together with the above response for this question and the earlier response for the case with 2 letters between N and D, gives us:
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document.write( "0 letters between: 1440\r\n" );
document.write( "1 letter between:  1200\r\n" );
document.write( "2 letters between:  960\r\n" );
document.write( "3 letters between:  720\r\n" );
document.write( "4 letters between:  480\r\n" );
document.write( "5 letters between:  240\r\n" );
document.write( "         --------------\r\n" );
document.write( "           total   5040


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