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**1. Homework Statement**

An astronaut in his space suit and with a propulsion unit (empty of its gas propellant) strapped to his back has a mass of 143 kg. During a space-walk, the unit, which has been filled with propellant gas, ejects some gas with a velocity of +30.9 m/s. As a result, the astronaut recoils with a velocity of -0.265 m/s. After the gas is ejected, the mass of the astronaut (now wearing a partially empty propulsion unit) is 167 kg. What percentage of the gas propellant in the completely filled propulsion unit was depleted?

**2. Homework Equations**

p=mv

**3. The Attempt at a Solution**

-.265(astronaut + gas) = 30.9 (gas)

-.265(143 + x) = 30.9x

-37.846 -.265x = 30.9x

31.165x = -37.846

x = 1.214 kg

i dont really know where to go from here... can someone please help?