13. The volume of the box is the product of length, width, and height. The diagonal measure (5 cm) is of no use when finding the volume.
14. Density is the ratio of mass to volume (which should be obvious by the units—grams divided by cm³). You have
... (277 g)/(38 cm³) ≈ 7.3 g/cm³ . . . . . . matches the density of Tin