Official material: complete proof · OBMEP solutions · collection of the year. The resolutions below follow the numbering of the official notebook. Open the test to follow the statements, alternatives and diagrams; The explanations here are copyright. Attempt each question before checking the answer. Template Questions Answers 1–5 C · A · D · B · C 6–10 E · C · A · B · C 11–15 D · A · A · B · E 16–20 B · D · E · B · E Question 1 — Cans that support other cans Start from the blue can and mark the two that depend on it. Repeat the marking on the following layers: two cans, then two and, finally, the top can. These dependencies need to be removed from the top down; Removing cans from outside this set does not help release the blue one. There are $2+2+2+1=7$ cans before it. Alternative C.
Official material: complete proof · OBMEP solutions · collection of the year. The resolutions below follow the numbering of the official notebook. Open the test to follow the statements, alternatives and diagrams; The explanations here are copyright. Attempt each question before checking the answer. Question 1 — Wagons, colors and flags a) The white cars have numbers $1,4,7,10,\ldots$; with a flag, they must also be pairs. The first one after 8 is 10.
OBMEP 2021: Second Phase - Level 1 Exercise 1 On the board, each letter of the word OBMEP represents an integer from 1 to 5. Different letters represent different numbers. Furthermore, each number written on the side of the board is the sum of the values of the letters on the board. corresponding horizontal line. A) Find the value of the letter O. Response: 1 When we add the values from the first line, we have