[MATHS] Est-ce que l'élite peut m'aider à comprendre ce résultat ?

Est-ce que quelqu'un comprend quelque chose au résultat obtenu par rapport aux infos de la question

- We broke the country into 7 regions, all of which needed the same amount of street sweepers overall. In the north, on average there was a 22/8 ratio of mechanical to air sweepers needed. In the south, it was 22/18. For the country, what % of street sweeper sales were going to be that are mechanical?

- Roughly 66% (It’s actually 64%)