A snail is at the bottom of a well 30 feet deep. It crawls up 3 feet each day, but at night, it slips down 2 feet. How long does it take for the snail to crawl out the well?

30 days will required to reach the goal for the snail

30 days will required to reach the goal for snail

28 days.
On the last day he would have reached the top and escaped before sliding down that night.

27 days, since that's when he goes up another 3 feet and reaches the top. One that day, it doesn't matter that he slides down -- he's already out!

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My interests include inconel valves from The Alloy Valve Stockist, Barcelona, Spain at http://alloy-valves.com

Depends what you class as the first day...
(Current position)

Day 1: Up 3 (3) Night 1: Down 2 (1)
Day 2: Up 3 (4) Night 2: Down 2 (2)
Day 3: Up 3 (5) Night 3: Down 2 (3)
.
.
.
Day 26: Up 3 (28) Night 26: Down 2 (26)
Day 27: Up 3 (29) Night 27: Down 2 (27)
Day 28: Up 3 (30) Escape!