5. On the glade, there are 6 fewer bushes than trees. Birds flew in and sat both on the bushes and on the trees. They sat so that there were an equal number of birds on all the trees and an equal number of birds on all the bushes, but there were at least 10 more birds on a tree than on a bush. There were a total of 128 birds on the trees. How many bushes were there?
Answer: 2.

Solution: There are no fewer than 7 trees, as there are 6 more trees than shrubs. There are no fewer than 11 birds on one tree, as there are at least 10 more birds on one tree than on one shrub. There cannot be 12 or more trees, as then there would be $12 \cdot 11=$ 132 or more birds on the trees. Therefore, the number of trees can be 7 or 8 or 9 or 10 or 11. However, among these, only the number 8 is a divisor of the number 128. Therefore, there are 8 trees, and 6 fewer shrubs, which means 2 shrubs.

Comment: Correct solution - 20 points. There are gaps in the justification - 15 points. The problem is solved by trial and error, and it is not shown that there are no other options - 10 points. The solution is started, and there is some progress - 5 points. The solution is started, but the progress is insignificant - 1 point. The correct answer is given without explanation - 1 point.

## Variant 2