Need help with part a) 6 marks

Drilling occurred at the depth 7 km. The required bottom-hole pressure at this depth to keep the wellbore stable 100 MPa. The drilling mud is made of water, polymer and barite. 2 kg of polymer is added per 1 m3 of water to ensure that the fluid is viscous enough to suspend the barite particles. 400 tonnes of barite is available for the mud. Take the acceleration due to gravity as g = 9.81 m/s2. Densities: Barite - 4200kg/m3 Polymer 2000kg/m3 Water - 1000kg/m3 a) (2 marks) Calculate the density of mud needed to keep the borehole stable. (4 marks) Calculate the amount of water needed to achieve the required mud density to keep the borehole open