Wrong and wrongly are both adverbs, meaning incorrectly, badly, or mistakenly. Usage authorities differ on whether using wrong this way is acceptable, but in real-world usage, the adverbial wrong is not just widely accepted but common.
The adverbial wrong always follows the verb it modifies (e.g., he answered wrong). It also follows the object of the verb if there is one (e.g., he answered the question wrong). And wrongly can go either before or after its verb (e.g., he was wrongly imprisoned by the state; the state imprisoned him wrongly).
In any case, keep in mind that some consider the adverbial wrong incorrect, so writers who wish to play it safe should stick with wrongly in more formal communication.
Yet the average Democrat respondent got nearly 60 percent of the answers wrong. [American Spectator]
The patients also argue that the laws wrongly give local cities and counties the ability to ban marijuana dispensaries. [KRDO.com]
Then in 1979, all sorts of things went wrong for Carter. [Daily Tribune]
[H[e often answered wrongly on purpose to amuse the class. [The Observer]
An online subheading and picture caption wrongly stated that Ian Edmondson, assistant editor (news) at the News of the World, had been sacked. [Guardian]