"How is it possible?"
Translation:Hur är det möjligt?
You mean you'd like to put Hur går det? as an answer here? Det går does mean 'It is possible', but Hur går det? is very tied up to the meaning 'How is it going?' or 'How are things going?', so we would probably not interpret it as 'How is it possible?'. I've discussed this with the other mods and they feel the same, we would like to add something, like Hur kan det gå? or Hur går det ihop? or make some other change to the sentence to make it mean that.