$45,000 allows you an awesome lifestyle in MOST parts of america!!! I make like half that and do just fine.
Not sure if the Big Mac cost in India would be relevant to the study, as I am pretty sure they don't eat beef there (so it isn't the same product to begin with), and I would imagine McD's would be more of a rare novelty type higher priced place in India as opposed to food for the masses.
Of course I am not sure where those Big Mac prices are even coming from, as they vary wildly from location to location WITHIN THE SAME TOWN. My local McD's charges like $2.09 for them, not $3.xx