The maximum mass of the product that may be formed if you have 60 grams of Mg and 16 grams of O2 available depends on the chemical reaction taking place. Magnesium reacts with oxygen to form magnesium oxide, which has the formula MgO. The balanced chemical equation for this reaction is:
Mg + O2 -> MgO
Using the mole concept and stoichiometry, you can determine the maximum mass of MgO that may be formed. However, without more information on the reaction, it is not possible to determine the maximum mass of the product that may be formed with 60 g Mg and 16 g O2