MathDB
Turkey NMO 2006 1st Round - P08 (Combinatorics)

Source:

February 2, 2013

Problem Statement

Let d1d_1 and d2d_2 be parallel lines in the plane. We are marking 1111 black points on d1d_1, and 1616 white points on d2d_2. We are drawig the segments connecting black points with white points. What is the maximum number of points of intersection of these segments that lies on between the parallel lines (excluding the intersection points on the lines) ?
<spanclass=latexbold>(A)</span> 5600<spanclass=latexbold>(B)</span> 5650<spanclass=latexbold>(C)</span> 6500<spanclass=latexbold>(D)</span> 6560<spanclass=latexbold>(E)</span> 6600 <span class='latex-bold'>(A)</span>\ 5600 \qquad<span class='latex-bold'>(B)</span>\ 5650 \qquad<span class='latex-bold'>(C)</span>\ 6500 \qquad<span class='latex-bold'>(D)</span>\ 6560 \qquad<span class='latex-bold'>(E)</span>\ 6600