Halliday, Resnick & Walker — Circuits: Problem 42

42 In Fig. 27-43, the ideal batteries have emfs \(\mathcal{E}_1 = 200 \text{ V}\) and \(\mathcal{E}_2 = 50 \text{ V}\) and the resistances are \(R_1 = 3.0 \;\Omega\) and \(R_2 = 2.0 \;\Omega\). If the potential at \(P\) is \(100 \text{ V}\), what is it at \(Q\)?