Well, maybe I can answer this for... other people, if not you.
Gas solubility is mathematically given, for ideal solutions, by Henry's law. For MasteringChemistry-related problems, this version is appropriate:
s=kHPgaswhere:s is the solubility in mol/L of the gas.kH is the Henry's law constant in M/atm.Pgas is the vapor pressure of the gas above the surface of the liquid.