(1) At the same time and in different directions, Party A and Party B look at a whole, with the speed of 16m/s and the time of 400/ 16.

(2) At the same time, in the same place, in the same direction, A is 2 meters faster than B. It takes 400/2=200 seconds for A to catch up with B for the first time.

(3) The second meeting will take time multiplied by 2.