Three cubes, of sides l0 = 2l0 3l0, are placed next to one another (in contact) with

Question:

Three cubes, of sides l0 = 2l0 3l0, are placed next to one another (in contact) with their centers along straight line and the l = 2l0 cube in the center (Fig 7-39). What is the position, along this line, of the CM of this system? Assume the cubes are made of the same uniform material.