## Task 1 - 120511

At a birthday party, Rainer presents his guests with the following puzzle, known since ancient times:

A snail begins at the beginning of a day to climb a $10 \mathrm{~m}$ high wall from the ground. In the following time, it crawls up $5 \mathrm{~m}$ higher during the first 12 hours of each day and slides down $4 \mathrm{~m}$ during the remaining 12 hours of the same day.

After how many hours has it first reached the entire height of the wall?
After 12 hours, the snail reaches a height of $5 \mathrm{~m}$, but in the following 12 hours, it slips back $4 \mathrm{~m}$.

Thus, it starts the 2nd day at a height of $1 \mathrm{~m}$, the 3rd day at $2 \mathrm{~m}$, and so on. On the 6th day, it begins at a height of $5 \mathrm{~m}$ and after $12 \mathrm{~h}$, it reaches the required height of 10 meters.

Since it crawled and slipped back for 5 days, and on the 6th day, it reached the goal after 12 hours, it took $5 \cdot 24+12=132$ hours.