"How many days did a trip take from Prague to Germany two centuries ago?"
This would seem to also be correct... ie. "a trip takes how long?"
It is an awkward word order, and it is not accepted.
I am English and I agree with rosemarie45933. Her sentence is fine with me.
Proč "trip"? Proč ne "way"?
"way" je cesta ve významu "silnice", ne ve významu "jízda" nebo "cestování"
"Way" can also convey a sense of direction, as in a "one-way trip."
'How many days did a journey from prague to germany take two centuries ago'. Why is this wrong?
We had an error which I fixed.
Why is is před dvěma stoletími and not před století?
"před" takes the instrumental case, which in plural happens to be "stoletími". https://prirucka.ujc.cas.cz/?slovo=stolet%C3%AD