In component form, the displacement vectors become
• 350 m [S]   ==>   (0, -350) m
• 400 m [E 20° N]   ==>   (400 cos(20°), 400 sin(20°)) m
(which I interpret to mean 20° north of east]
• 550 m [N 10° W]   ==>   (550 cos(100°), 550 sin(100°)) m
Then the student's total displacement is the sum of these:
(0 + 400 cos(20°) + 550 cos(100°), -350 + 400 sin(20°) + 550 sin(100°)) m
≈ (280.371, 328.452) m
which leaves the student a distance of about 431.8 m from their starting point in a direction of around arctan(328.452/280.371) ≈ 50° from the horizontal, i.e. approximately 431.8 m [E 50° N].
 
        
             
        
        
        
True, they have zero electrical resistance.
        
             
        
        
        
The most common liquid on planet earth is water
        
             
        
        
        
15.277.. j. I did the problem using a proportion. an additional 3.7m to the current 1.8 cm=5.5cm.
Therefore, 5.0 j/1.8cm=x/5.5cm