The balanced chemical reaction would be
4Fe(s) + 3O2(g) ---> 2Fe2O3(s)
We are given the amount of Fe to be used in the reaction. We use this as the starting point for the calculations. We do as follows:
25.9 g Fe (1 mol / 55.85 g) ( 2 mol Fe2O3 / 1 mol Fe ) (159.69 g / mol ) = 262.48 g Fe2O3 produced
