8. A snail is crawling from one tree to another. In half a day, it crawled $l_{1}=4$ m. It realized it was all too much and turned back. It crawled $l_{2}=3$ m. It got tired. It fell asleep. The next day, everything repeated. And so every day. The distance between the trees is $s=40$ m. On which day of its journey will the snail reach the tree? (10 points)
Answer: on the 37th day

Solution. In one day, the snail advances towards the other tree by:

$\Delta l=l_{1}-l_{2}=1$ m (3 points). At a distance of $l_{1}=4$ m (i.e., one transition) from its goal, it will be after 36 days of travel (4 points). Therefore, the goal will be reached on the 37th day of travel (3 points).

## Tasks, answers, and evaluation criteria

6th grade

![](https://cdn.mathpix.com/cropped/2024_05_06_21b93289ab9f0d96989eg-5.jpg?height=128&width=551&top_left_y=690&top_left_x=867)