Balance constant inflow against volume-dependent outflow

A tank initially contains $2\,\mathrm{m}^3$. Water enters at $4\,\mathrm{m}^3\mathrm{s}^{-1}$ and leaves at a rate proportional to the volume $V$. When $V=6\,\mathrm{m}^3$, the net rate is $1\,\mathrm{m}^3\mathrm{s}^{-1}$. Set up and solve a differential equation to show $V=8-6e^{-0.5t}$.7 marks

(i) Describe what happens to the volume eventually.1 mark

(ii) Sketch $V$ against $t$.2 marks