In summer of $2021,$ the Benjamin Mkapa Hospital admitted $40$ patients with an average weight of $165$ pounds who were bitten by venomous cobra snake. Despite all the efforts to save these patients, the doctors could not save the lives of $20$ patients. If the snake's venom has a rat LDs of approximately $0\mathrm{.}05$ mg$/$kg and density of $1$ g$/$ml$,$ determine the volume of venom required to cause such response to human.