The snail is going to climb a tree 10m a day it crawls 5m and at night it slides 2m down on what day it will crawl to the top.

We determine to what height the snail rises in a full day.

To do this, we subtract 2 meters of descent from 5 meters of ascent.

5 – 2 = 3 meters.

In this case, in 2 full days, it will rise to a height:

3 * 2 = 6 meters.

Thus, for the day of the third day, its height will be:

6 + 5 = 11 meters.

Answer: The snail will reach the top of the tree on day 3.