olymmath

AMC 12 2023a Problem 21

  • Paper

If AA and BB are vertices of a polyhedron, define the distance d(A,B)d(A, B) to be the minimum number of edges of the polyhedron one must traverse in order to connect AA and BB. For example, if AB‾\overline{AB} is an edge of the polyhedron, then d(A,B)=1d(A, B) = 1, but if AC‾\overline{AC} and CB‾\overline{CB} are edges and AB‾\overline{AB} is not an edge, then d(A,B)=2d(A, B) = 2. Let QQ, RR, and SS be randomly chosen distinct vertices of a regular icosahedron (regular polyhedron made up of 20 equilateral triangles). What is the probability that d(Q,R)>d(R,S)d(Q, R) > d(R, S)?

\textbf{(A)}\frac{7}{22} \textbf{(B)}\frac13 \textbf{(C)}\frac38 \textbf{(D)}\frac5{12} \textbf{(E)}~\frac12

Dataset text AMC 12 2000 to 2025. Quoted with source.

Show the answer

A

Solutions

No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.

Add a solution

Similar problems

These problems have the most words in common with this statement.

Locator amc12/2023a/p21 · Tag Q4RQ77JVJB · Edit this page on GitHub · Keys: j next, k previous