MathDB
Distinct planes intersecting cube

Source: 2012 AMC 12A Problem #22

February 8, 2012
geometry3D geometrytetrahedronprismAMC

Problem Statement

Distinct planes p1,p2,....,pkp_1,p_2,....,p_k intersect the interior of a cube QQ. Let SS be the union of the faces of QQ and let P=j=1kpj P =\bigcup_{j=1}^{k}p_{j} . The intersection of PP and SS consists of the union of all segments joining the midpoints of every pair of edges belonging to the same face of QQ. What is the difference between the maximum and minimum possible values of kk?
<spanclass=latexbold>(A)</span> 8<spanclass=latexbold>(B)</span> 12<spanclass=latexbold>(C)</span> 20<spanclass=latexbold>(D)</span> 23<spanclass=latexbold>(E)</span> 24 <span class='latex-bold'>(A)</span>\ 8\qquad<span class='latex-bold'>(B)</span>\ 12\qquad<span class='latex-bold'>(C)</span>\ 20\qquad<span class='latex-bold'>(D)</span>\ 23\qquad<span class='latex-bold'>(E)</span>\ 24