4. Four friends - Alexei, Boris, Viktor, and Gennady went fishing. Boris caught more fish than Alexei and Viktor together. Boris and Alexei together caught as much as Viktor and Gennady, and Boris and Viktor together caught less than Alexei and Gennady. Arrange the friends in the order of the amount of fish caught, from most to least.
Answer: In descending order of catch: Gennady, Boris, Alexei, Viktor.

Solution. According to the problem, B > A + V, A + B = V + G, A + G > B + V. From this, B > A, V + 2G = G + (B + G) = G + A + B = (G + A) + B > 2B + B, which means G > B. Therefore, A + G > A + B = B + G, which means A > V. Consequently, G > B > A > V.

## Evaluation Criteria:

- correct answer with full justification - 7 points;
- correct answer and generally correct justification, with gaps or inaccuracies - 5 points
- proved that B > A - 1 point;
- proved that B > A and G > B - 3 points;
- correct answer without justification - 2 points;
- incorrect answer - 0 points.