Suppose that one-half the mass of the sphere has a density

Question

Problem: Suppose that one-half the mass of the sphere has a density of 2.70 x 10³ kg/m3, 0.33 times the mass of the sphere has a density of 7.80 x 10³ kg/m³, and 0.17 times the mass of the sphere has a density of 11.3 x 10³kg/m³.

Part A: What is average density of the sphere?

Please explain how you came to your conclusion to determine average density of the sphere? Given that the mass is 2.55 kg.