"Where can you buy a ticket?"
Translation:Waar kan je een kaartje kopen?
When translating from english to dutch I think 'je' and 'jij' should both be accepted here.
No Dutch speaker would use "jij" here. The English sentence uses an impersonal "you" that should be translated with "je". Using "jij" sounds like you are speaking to a person who has to buy a ticket at a different place from anybody else instead of asking where one can buy a ticket.