Explanation:

Point A is the home of abhijeet, he moves 30 m in north west direction from point A and reaches point B, from point B he again moves
30 m in south west direction top reach point C, then he moves 30 m in south-east direction to reach point D, and finally he moves 30 m
in north-east direction to return back to point A.
therefore the distance between abhijeet's home to the end point is 0.
This is a direct explanation. Take step by step. Like he moved 30m north west. So represent it in the figure 1.
Then 30m south west. Represent it in figure 2 combining figure 1 and likewise.