"You are fast, we are slow."
Translation:Tu ești rapid, noi suntem înceți.
"Voi" is you plural. "Tu" is you singular. Why would I be wrong in assuming the phrase "You are fast..." is "Tu ești rapid.."? If the sentence was "You guys are fast" then I would have an indication that this is meant to be plural. I don't think the team creating these are evaluating these sentences closely enough.
The translation team seem to overlook many possible meanings of the phrases. It's not the first time a correct (but different) answer is not being accepted.