Hi Nina!
As the case states, "The required net working capital amounts to 5% of the turnover"
Exhibit 1 shows the turnover in the last row (Turnover of Parking App).
As such, from that exhibit we know that the turnover in 2021 is 1.428M Euro. 5% of that is 71,400 Euro.
In 2020, our NWC was 17,850. Therefore, the change (delta) in NWC was 71,400 - 17,850 = 53,550.
Et voila!
