"There are forty-seven spiders there already."
Translation:Pavouků tam už je čtyřicet sedm.
No jo, kdyby to zaznělo rovnou, dávno to mohlo být spraveno... Přidávám.
Why is this word order correct instead of "Tam je už čtyřicet sedm pavouků." or "Už je čtyřicet sedm pavouků tam."?
The first one is possible, but stressing a different thing. In the official answer we know we are talking about spiders there and the new info is their number. In your sentence even the fact there are any spiders there is probably new.
The other one is not Czech, we do not put the adverb of location at the end as English does.
But don't get the impression that "tam" cannot be at the end at all. It can. "... pavouků už je tam." is possible. Especially when you were putting there and you are finished now.