Question 930337
(a) At least how many of these "words" should be printed to be sure of having at
least 7 identical "words" on the list? 
<pre>
There are 26 ways to choose the first letter, 25 to choose the 2nd letter, 24
ways for the 3rd and 23 for the 4th, so there are 26*25*24*23 = P(26,4)= 358800
possible "words".

If there were 6*358800 or 2152800 words on the list, there would be a very
slight chance that there were exactly 6 duplicates of each word.  However to
eliminate that rare case, if there were 1 more word, or 2152801, on the list,
there would necessarily be 7 duplicates of some word.

Answer: 2152801.
</pre>
(b) At least how many identical "words" are printed if there are 2870401 "words"
on the list? 
<pre>
We divide 2870401 by 358800 

      <u>       8</u>
358800)2870401
       <u>2870400</u>
             1

We get 8 with 1 remainder.

So there is a slight chance that the 2870401 consists of exactly 8 duplicates of
each of the 358800 words, plus 1 more word.  So there are at least 9 duplicates
of some word on the list.

Edwin</pre>