I'm thinking of someone saying it on a market stall while pointing to a sign with the price on it. Probably with a grumpy expression while thinking 'Why are you asking me when it's clearly written right in front of you?'.
It is, usually. The 'n version should come up as a prompt about half the time, and it is always accepted as an answer. The yn version will be removed for Tree2 - we cannot easily remove it from the current version of the course.