Question

a snail fell into a hole 30m deep. it starts to climb up. every day it climbs 3m and every night it slides down 2m. after how many days will the snail emerge from the hole?

Answer 1

3-2+3-2+3-2+... = 30
After 26 days, it would have climbed up 27m
Hence the following day it would emerge from the hole, making it 27 days in total.

Answer 2

Sorry:
After 27 days, it would have climbed up 27m
Hence the following day it would emerge from the hole, making it 28 days in total.