Applying $K V L$ in loop $A B C D A, A B F E A, A B G H A$ and $A B I I A$, we get
$$
\begin{aligned}
& 30-i_1 \times 11=-25 \\
& 20+i_2 \times 5=25 \\
& 5-i_3 \times 10=-25 \\
& 10+i_4 \times 5=25
\end{aligned}
$$
Solving equations (i), (ii), (iii) and (iv) we get $i_1=5 \mathrm{~A}, i_2=1 \mathrm{~A}, i_3=3 \mathrm{~A}$ and $i_4=3 \mathrm{~A}$.
Hence, current flowing through $25 \mathrm{~V}$ cell is $12 \mathrm{~A}$.