The circuit is shown, in figure. Effective resistance
of combination of two resistors (4Ωeach) in parallel is
Req=(4x4)/(4+4)=2Ω

Since the resistor of 2Ω and parallel combination of two 4Ω resistors are in series, the same current will flow through these. Hence, the potential difference across 2Ω resistor is same as that across a combination of two resistors.