Can anyone helps me answering this ?

2) A 22L helium tank is to be filled with high pressure helium. The density of helium can be approximated using the ideal gas law. A) Derive an equation for the pressure in the tank as a function of time assuming that the inlet mass flow rate into the tank is a constant (mim), that the temperature in the tank is constant, and that the initial pressure in the tank is 0.1atm. B) Derive an equation for the pressure in the tank as a function of time assuming that the inlet mass flow rate into the tank is given as mie=k(PinP) where Pin is the constant pressure in the helium feed to the tank, P is the pressure in the tank, and k is a constant. C) How long will it take to fill the tank to a pressure of 2.0104psi if the initial He pressure in the tank is 1.0atm,k=5.0g/atm/min, Pin. 0103atm, and T=300K