John Toczek

First to
Ground Floor
1 8? 56 35 B
2 66 9? 35 A
3 95 66 25 B
4 8? 116 85 B
5 11? 55 85 A
6 76 45 5? A
7 75 55 12? C
8 56 85 126 A
9 25 12? 55 B
10 75 55 12? C
11 25 4? 66 ??

The building I work in has three elevators and 12 floors. Like some elevators, these have displays above them that indicate the current floor that the elevator is on and also the travel direction of the elevator.

The travel direction display can show Up, Down or Stopped indicated by an up arrow, a down arrow or a dash character, respectively. As an example, Elevator A in the image is on the 2nd floor and is traveling in the up direction.

Table 1 displays 10 historic data points showing the floor and direction of the elevators from times that I have used the elevator in the past. The table also shows which elevator showed up first on the ground floor.



For scenario No. 11, which elevator is most likely to be first to the ground floor?

Send your answer to puzzlor@gmail.com by Aug. 15. The winner, chosen randomly from correct answers, will receive a $25 Amazon Gift Card. Past questions and answers can be found at puzzlor.com.

John Toczek is the assistant vice president of Predictive Modeling at Chubb in the Decision Analytics and Predictive Modeling department. He earned his BSc. in chemical engineering at Drexel University (1996) and his MSc. in operations research from Virginia Commonwealth University (2005).