Get population estimate for all countries with adword revenue, get adword revenue for each of these countries, fit to a linear model, predict italy. Or calculate adword revenue per capita and apply.
Sorry, that's not close enough. Can you do better?
(For the record, the person you originally responded to did not share that question with the intention of you actually trying to answer it. The point was the illustrate how ludicrous some of those questions are. You don't have access to any of the information that you mentioned in your response in the interview.)
