Explanation:
In the interference of two waves , these will fall upon each other .
It will make nodes and anti-nodes in between . There will be one node in between two anti-nodes and will be one anti-node between two nodes .
The distance between two nodes is λ/2 and distance between two anti-nodes is also λ/2
Thus if the man is at constructive interference , so to move at destructive interference , it has to cover a distance equal to λ/4
Here λ = velocity/frequency = 344/632 = 18.4 m
Thus the distance he will cover = 18.4/4 = 4.6 m