Six heures cinquante?

Question

The question was 
Il est ________ .It's ten to seven AM.

Why was six heures cinquante marked incorrect?

Accepted Answer

Bonjour William !
The question is asking specifically to say "it is ten to seven", which is a more complex structure than simply saying "it is six fifty". It's also much more colloquial to use the "to" structure in French, just like it is in English, hence us testing that specific expression :)
I hope that answers your question :)
Bonne journée !

Answer

Hi William ,
Was it in the evening? In which case it would be dix-huit heures cinquante , or sept heures moins dix...

Answer

No it was in the morning the question is as shown above

Answer

"dix-huit heures cinquante" for ten seven PM was marked incorrect. Why?

Answer

I agree it's not clear. Je viens de faire la même erreur... A Hint would be appreciated wherever right answers will not be accepted.