1011.5: Seminar Seating Solution
Congratulations to Endrit Beja ‘11 for winning the contest!
Other correct entries were submitted by Andrew Harris’11, Jack Kissel ‘13, Lauren Lanzotti ‘14, Amelia Mattern ‘12, Trang Nguyen ‘13, Chris Smith ‘11, Evan van Tassell ‘13, Ian Thresher ‘12, and John Whitney ‘12; and Anne Kinnel.
In our last puzzle, you were asked to seat six philosophy students around a small table.
Arthur, Cora, and Elizabeth are majors, while Bas, David, and Frances are minors. Arthur and Bas are sitting to the immediate left of a major. Cora and David are sitting to the immediate right of a minor. Elizabeth and Frances sit directly across from a minor. The person presenting his seminar paper is on the immediate left of a major, and directly across from a minor.
Since Elizabeth, a major, and Frances, a minor, each sit across from minors, there must be two majors sitting across from each other: Arthur and Cora. Since Arthur must sit to the left of a major, he must sit on Elizabeth’s left. David has to sit to the right of a minor, but Bas has to sit to the left of a major, so David sits on Frances’s right. Since Frances has to sit across from a minor, she must sit across from Bas. Since Elizabeth must sit across from a minor, and Bas and Frances are sitting across from each other, Elizabeth must sit across from David. The following three seating charts are possible, so far:
Case 3 has Cora sitting to the right of Elizabeth, a major, so that’s out. In both cases 1 and 2, Bas is the only person sitting to the left of a major and across from a minor. So, Bas is presenting, and either seating arrangement 1 or 2 will work.