Answer
The horizontal distance between the center of container 1 and the center of mass is $~~25~mm$
Work Step by Step
Initially, both containers have the same mass. Since the centers of the containers are a distance of $50~mm$ apart, then by symmetry, the horizontal distance between the center of container 1 and the center of mass must be half of this distance.
Therefore, the horizontal distance between the center of container 1 and the center of mass is $~~25~mm$.
