Checklist VsOSh AI 2026 School Stage (Sirius platform, region group 4), grades 9–11 · Task 4
Falsifying a Hypothesis
Russian title: Задание 4
Choose two test triples whose yes/no answers identify which of four rules generated the triple 1, 2, 4.
The task
A teacher chose a rule satisfied by the triple 1, 2, 4; it is one of four: the numbers strictly increase; all numbers are positive; any three numbers fit; the product of the first and last numbers equals the square of the second.
Choose two triples of integers such that the pair of yes/no answers determines the rule uniquely.
Abridged and translated by SOTA from the official Russian materials. The official statement has the exact rules, and it wins wherever this summary differs.
In English
This task was published in Russian. SOTA translated its 3 files into English on 16 September 2026.
- Task statement Russian original of Task statement
- Official solution Russian original of Official solution
- Full paper with solutions (all tasks of the tour) Russian original of Full paper with solutions (all tasks of the tour)
Read the task statement in English
Falsifying a Hypothesis
English translation by SOTA – AI Community of the Russian original. Organisers who would like this translation removed can email [email protected].
Task 4 of the school stage of the All-Russian School Olympiad (VsOSh) 2025/26 in artificial intelligence (region group IV), grades 9–11. The official answer and solution are in a separate file.
A teacher explains to the children that if they want to test a hypothesis, they must try to refute it. He has thought of a rule that the triple of integers 1, 2, 4 satisfies. It is known that this rule is one of four:
- the numbers are strictly increasing;
- all the numbers are positive;
- any three numbers fit;
- the product of the first and the last numbers equals the square of the second.
Choose two triples of numbers such that the pair of “yes/no” answers makes it possible to determine unambiguously which of the four rules has been thought of:
[The answer options are not listed in the original file; the table in the solution considers the triples (1, 2, 4), (1, 2, 3), (−3, −3, −3) and (−3, −2, −1).]
Scoring criterion: (Number of correct choices minus number of incorrect ones) × 6, maximum 12 points
Maximum score for the task — 12
Translated by SOTA. The Russian original is the official version and wins wherever the two differ. Statement and official solution come from one PDF, the analysis of the school-stage tasks for region group IV, grades 9–11, linked from the olympiad's Sirius page. The published file does not list the answer options; a translator's note names the triples compared in the official solution. If you organise this olympiad and would like the translation removed, email [email protected] and we will take it down.
At a glance
- You get
- Statement only.
- You submit
- Two triples (selected from options).
- Scoring
- (correct selections − incorrect selections) × 6 points (maximum 12).
- Format
- School stage on the Sirius.Courses platform, region group 4, 21 October 2025; grades 9–11; individual; 150 minutes; maximum 112 points for the paper (tasks 1–6: 12 points each; tasks 7–8: 20 points each).