Electrochemistry

Consider a Galvanic cell in which the following reactions occurs: $\mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{Ag}^{+}(\mathrm{aq}) \rightarrow \mathrm{Fe}^{3+}(\mathrm{aq})+\mathrm{Ag}(\mathrm{s})$. What is the standard potential of the cell? Given: $\mathrm{E}^0\left(\mathrm{Ag}^{+} / \mathrm{Ag}\right)=\mathrm{aV} \quad \mathrm{E}^0\left(\mathrm{Fe}^{2+} / \mathrm{Fe}\right)=\mathrm{bV} \quad & \quad \mathrm{E}^0\left(\mathrm{Fe}^{3+} / \mathrm{Fe}\right)=\mathrm{cV}$