Question 22
The vertices of triangle PQR are lattice points on the surface of a 3×3×3 cube. P and Q lie on side faces, and R lies on the top face. If the triangle is right-angled at Q, which labelled point is R?
Original printed choices: A) At A; B) At B; C) At C; D) At D; E) At E
Editorial task: Use the lattice diagram to test all five candidates and determine whether the printed question has a unique answer. Explain what the source solution overlooks.
Original printed choices: A) At A; B) At B; C) At C; D) At D; E) At E
Editorial task: Use the lattice diagram to test all five candidates and determine whether the printed question has a unique answer. Explain what the source solution overlooks.