MathDB
Turkey NMO 2010 1st Round - P16 (Combinatorics)

Source:

July 26, 2012
countingdistinguishability

Problem Statement

1111 different books are on a 33-shelf bookcase. In how many different ways can the books be arranged such that at most one shelf is empty?
<spanclass=latexbold>(A)</span> 7511!<spanclass=latexbold>(B)</span> 6211!<spanclass=latexbold>(C)</span> 6812!<spanclass=latexbold>(D)</span> 1213!<spanclass=latexbold>(E)</span> 613! <span class='latex-bold'>(A)</span>\ 75\cdot 11! \qquad<span class='latex-bold'>(B)</span>\ 62\cdot 11! \qquad<span class='latex-bold'>(C)</span>\ 68\cdot 12! \qquad<span class='latex-bold'>(D)</span>\ 12\cdot 13! \qquad<span class='latex-bold'>(E)</span>\ 6 \cdot 13!