Atoms of an element A (molecular mass =100) are arranged as close packing consists of a first layer of atoms A, followed by a second layer where each atom of A rests over the depression formed by four atoms of A of first layer. Atoms of A are then arranged in third layer rests on second layer such that arrangement corresponds exactly to that in the first layer. This pattern continued above and below of the first layer to form infinite lattice. Atoms of element B (molecular mass 200) occupied all largest voids. What is the mass percentage of B in the crystal?