For the redox reaction,
MnO4-+C2O42-+H+→Mn2++CO2+H2O
The correct coefficients of the reactants for the balanced equation are
16MnO4- +5C2O42-+2 H+
2MnO4-+5C2O42-+16 H+
2MnO4-+16C2O42-+5 H+
5MnO4-+16C2O42-+2 H+
The correct balanced equation is
2MnO4-+5C2O42-+16H+⟶2Mn2++10CO2+8H2O