Test

Prompt

A snail is at the bottom of a 30m well. Each day it climbs up 3m, but at night it slides down 2m. However, every 4th day (4th, 8th, 12th...), it doesn't slide back at night because it rests on a ledge. On what day does it reach the top? Show your full reasoning step by step, and double check your arithmetic at the end.