The EMF of the following cells are 

$\begin{array}{l}\mathrm{Cu}\left|{\mathrm{Cu}}^{2+}\left(1\mathrm{M}\right)\parallel {\mathrm{Ag}}^{+}\left(1\mathrm{M}\right)\right|\mathrm{Ag},{\mathrm{E}}^0=0.46\mathrm{V}\\ \mathrm{Zn}\left|{\mathrm{Zn}}^{2+}\left(1\mathrm{M}\right)\parallel {\mathrm{Cu}}^{2+}\left(1\mathrm{M}\right)\right|\mathrm{Cu},{\mathrm{E}}^{\mathrm{o}}=1.10\mathrm{V}\end{array}$
The EMF of the cell 

$\mathrm{Zn}\left|{\mathrm{Zn}}^{2+}\left(1\mathrm{M}\right)\parallel {\mathrm{Ag}}^{+}\left(1\mathrm{M}\right)\right|\mathrm{Ag}\text{ will be }$

$\mathrm{Cu}+2{\mathrm{Ag}}^{+}\to 2\mathrm{Ag}+{\mathrm{Cu}}^{+2} {\mathrm{E}}_1^0=0.46\mathrm{V}$
$\mathrm{Zn}+{\mathrm{Cu}}^{2+} \to {\mathrm{Zn}}^{2+}+\mathrm{Cu} {\mathrm{E}}_2^{\mathrm{o}} = 1.10 \mathrm{V}$
$\mathrm{Zn}+2{\mathrm{Ag}}^{+}\to {\mathrm{Zn}}^{2+}+2\mathrm{Ag} {\mathrm{E}}_3^{\mathrm{o}}$
${\mathrm{G}}_3^{\mathrm{o}} = {\mathrm{G}}_1^{\mathrm{o}}+{\mathrm{G}}_2^{\mathrm{o}}$
${\mathrm{nFE}}_3^{\mathrm{o}} = {\mathrm{nFE}}_1^{\mathrm{o}}+{\mathrm{nFE}}_2^{\mathrm{o}}$ n is 2 in all
Hence 
$$\begin{gathered} {\mathrm{E}}_3^{\mathrm{o}} = 0.46\mathrm{V}+1.10 \mathrm{V} \\ = 1.56 \mathrm{V} \end{gathered}$$