A cube, a cuboid, a cone and a sphere were developed from an experimental material. In vacuum, the combined mass of the cuboid and the sphere is equivalent to the combined mass of the cube and the cone. The mass of the cuboid is equivalent to the combined mass of the sphere and the cone. The sphere weighed 2 kilograms and occupied a volume of 62.5 cubic cm in vacuum. One of the properties of this material is such that the length of the side of the cube doubles when exposed to air. How many cubes are needed to fill a tank of dimension 50 cm x 50 cm x 50 cm in air?