Concept:Track each turn carefully using directions. A right turn changes the facing direction clockwise by 90∘.Explanation:Start facing West and walk 4 km West.Turning right while facing West means he now faces North. He walks 4 km North.Turning right again while facing North means he now faces East. He walks 4 km East.The 4 km East cancels the initial 4 km West.So his net displacement is only 4 km North from the starting point.
