So i basically understood the whole question. But in the working capital computation i dont understand how he came to the figure of working capital cashflow for year four as 2.1.
At time 3, the level of working capital is 11.7. However at time 4, they only need working capital of 9.6. So the working capital reduces and therefore the difference (11.7 – 9.6) is recovered and there is therefore an inflow of the difference of 2.1.