A current of 15 mA flows in the circuit as shown in figure. The value of potential difference between the…

Using current division rule, 

Current, $i_1=\frac{5}{10+5}\times 15 \mathrm{mA}=5 \mathrm{mA}$

Now, using Kirchhoff's voltage law- in lower loop,

$V_A-5i-10i_1-10i=V_B$

Potential difference between $A$ and $B$ is $V_A-V_B=75+50+150=275 \mathrm{V}$