MathDB
P31 [Combinatorics] - Turkish NMO 1st Round - 2004

Source:

November 15, 2013

Problem Statement

For how many different values of integer nn, one can find nn different lines in the plane such that each line intersects with exacly 20042004 of other lines?
<spanclass=latexbold>(A)</span> 12<spanclass=latexbold>(B)</span> 11<spanclass=latexbold>(C)</span> 9<spanclass=latexbold>(D)</span> 6<spanclass=latexbold>(E)</span> 1 <span class='latex-bold'>(A)</span>\ 12 \qquad<span class='latex-bold'>(B)</span>\ 11 \qquad<span class='latex-bold'>(C)</span>\ 9 \qquad<span class='latex-bold'>(D)</span>\ 6 \qquad<span class='latex-bold'>(E)</span>\ 1