Answer
8.8 volts
Work Step by Step
For resistors in series, the equivalent resistance is their sum: $R_{eq}=R_1+R_2$.
The current in the entire circuit is the battery voltage divided by the equivalent resistance that it “sees”: $I=\frac{\epsilon}{R_{eq}}=\frac{\epsilon}{ R_1+R_2}$.
Finally, the voltage across the one of the resistors, say, $R_2$, is given by Ohm’s law, V=IR.
$$V_{R_2}=IR_2=\frac{\epsilon}{ R_1+R_2}R_2$$
$$ =\frac{12V}{650\Omega+1800\Omega}(1800\Omega)=8.8V$$