3. a turtle fell to the bottom of a deep well. the turtle climbed up 2 meters on the first day, but slipped back 1 meter as he rested. the second day, the turtle climbed double the distance of the previous day but slipped and lost 1/2 of the day's climbed distance as he rested. this pattern continued until the end of the fourth day, when the turtle realized he was halfway to the top of the well. how deep was the well?