Standard Cell Potential Calculation

For the given cell
Fe²⁺_­(aq) + Ag⁺(aq) → Fe³⁺ (aq) + Ag(s)
The standard cell potential of the above reaction is Given :
Ag⁺ + e^–  → Ag E⁰ = x V
Fe²⁺ + 2e^– → Fe            E⁰ = y V
Fe³⁺ + 3e^– → Fe            E⁰ = z V