An astronaut in his space suit and with propulsion unit (empty of its gas propellant) strapped to his back has a mass of 140kg.Through a space walk, the unit, which has been totally filled with propellant gas, ejects some gas with a velocity of +32m/s. As a result, the astronaut recoils by velocity of -0.35. After the gas is ejected, the mass of the astronaut (now wearing partially empty propulsion unit) is 165kg. What percentage of the gas propellant in the totally filled propulsion unit was depleted?