A cell of 8.0 V and 0.60 Ω is joined in series, opposing, with a cell of 2.0 V and 0.40 Ω…

Step 1. The current. $I = \dfrac{8.0\ \text{V} - 2.0\ \text{V}}{3.0\ \Omega + 0.60\ \Omega + 0.40\ \Omega} = \dfrac{6.0\ \text{V}}{4.0\ \Omega} = 1.5\ \text{A}$.

Step 2. The stronger cell. It discharges: $V = 8.0\ \text{V} - 1.5\ \text{A} \times 0.60\ \Omega = 7.1\ \text{V}$.

Step 3. The weaker cell. It is being charged: $V = 2.0\ \text{V} + 1.5\ \text{A} \times 0.40\ \Omega = 2.6\ \text{V}$.