The challenge
A manager leaves a locked office at 6 p.m. The next morning, a report is on the desk even though the lock log shows no entry. The report was not there when the manager left. How is that possible?
Locked Office Lateral Thinking Puzzle
Solve this medium lateral challenge, then compare your reasoning with the hint, checked answer, verification, and variation.
Hint
A locked door restricts people, not every way an object can move.
The evidence permits several delivery channels
The report could have been delivered through an internal document slot, printed remotely by a printer inside the office, or placed by someone already inside before the manager checked. The facts do not identify one answer, so a good investigation tests these channels rather than declaring a culprit.
Competing explanations and tests
- Separate the observed facts from the assumption that delivery required a new entry.
- Generate alternatives such as a document slot, remote printing, or a person already inside.
- Identify evidence that differs across alternatives, including printer logs, camera views, and access timing.
Incomplete evidence should produce tests
In real investigations, list multiple explanations and seek discriminating evidence.
Evidence needed to separate the channels
A defensible conclusion requires evidence that supports one channel while weakening the others. The prompt alone supports several answers.
A clever story is not proof
Choosing one clever answer and calling it proven ignores other explanations that fit the same facts equally well.
How confident were you?
List channels for people, paper, and output
The lock log constrains entry through the logged door, not every path by which a document can appear. List channels for people, paper, and digital output before selecting an explanation.
Remove two channels and test the remainder
Suppose the office has no slot and the printer was unplugged. What evidence would determine whether someone remained inside after 6 p.m.?
Study hypothesis-driven problem solving for the reusable method behind this challenge. Then explore the lateral thinking challenges learning path for connected examples and practice.