IMC 2021
contestants
589
problems
8 (4+4)
score scale
0–10
per-problem results
yes
Notes on this edition’s data
- Each problem marked out of 10.
- This edition had 8 problems (4+4).
Per-problem difficulty
Day 1
Day 2
Difficulty vs discrimination
Each dot is one problem. X — how many solved it (scored ≥ 8 of 10); Y — discrimination, i.e. how well the problem told strong contestants from weak ones (score-vs-total correlation).
A good problem sits high and away from the edges. Bottom-left dots separated nobody — almost everyone failed them the same way.
Problem statistics
Same data as the Day 1 / Day 2 charts above.
| # | difficulty | avg | solved | near-0 | disc | topics | |
|---|---|---|---|---|---|---|---|
| Day 1 | |||||||
| P1 | easy | 7.4 | 69% | 11% | 0.39 | linear algebra | |
| P2 | medium | 5.4 | 39% | 19% | 0.46 | probabilitycombinatorics | |
| P3 | very hard | 1.3 | 8% | 80% | 0.50 | sequences & seriesreal analysis | |
| P4 | killer | 0.1 | 1% | 98% | 0.21 | real analysis | |
| Day 2 | |||||||
| P5 | easy | 5.8 | 55% | 31% | 0.55 | linear algebra | |
| P6 | hard | 2.3 | 17% | 71% | 0.57 | group theory | |
| P7 | very hard | 0.9 | 6% | 92% | 0.42 | complex analysis | |
| P8 | killer | 0.0 | 0% | 99% | 0.08 | linear algebracombinatorics | |
Field cohort = total ≥ 3 points; difficulty is computed live by the API. Discrimination is the corrected item–total correlation.