The height of the pine is 20 m. A snail crawls along it, rising 2 meters every day and going down

The height of the pine is 20 m. A snail crawls along it, rising 2 meters every day and going down 1 meter every night. How many days will it take for a snail to climb to the top of a pine tree?

In the terms of the problem, it is said that the snail rises by 2 m per day and descends by 1 m during the night, which means the first action:

1.2 – 1 = 1m – this is how much a snail rises in a day.

In 18 days the snail will climb 18m.

2.18 x 1 = 18 m in 18 days.

And in another 1 days it will rise by 2m.

3.18 + 2 = 20 meters in 19 days.

Answer: 19 days.