Concept:Use direction changes to track net displacement from the starting point.Explanation:Let the house be at (0,0). West is negative x, East positive x, North positive y, South negative y.1. 15 km West → (−15,0).2. Turn left (South) 20 km → (−15,−20).3. Turn left (East) 25 km → (10,−20).4. Turn left (North) 20 km → (10,0).Final position is 10 km East of house, so distance = 10 km.Answer:10 km