Lessee -
"do Duke students take up part-time jobs, etc?" - some do. There are work-study jobs as part of financial aid packages; some lab/research jobs; some people get jobs in the surrounding area and whatnot. I would say it's a smallish number, generally
"how's the residence and food at Duke?" - since I live off-campus (because I'm...you know...old) and my freshman dorm is no longer a dorm, can't give you any recent feedback. For the latter, I eat two or three meals a day at Twinnie's, the cafe at Pratt, and like it a lot.
"How "cut-throat" is the competition at Duke? Is it competitive but supportive with students or is it extremely aggressive?" - By and large, I would say that students compete with the *courses* they take and not the students with whom they take them. The silver lining of any kind of grade inflation is the fact that - at least for me - there's no pressure to conform to some absolute grading scale or spectrum. If all my students performed really well one semester, then I give all A's - I am not going to try to turn a 93 into a C- just 'cause. Some of the larger classes can be competitive in terms of the students taking them, but I've not really heard of students comaplining about, say, people not sharing note or people not being open to forming study groups.
"How about asian Indian population at Duke? Any asian indian got it?" - I would certainly assume so based on past numbers
Diya is Duke's South Asian Student Association (I think it's cute that they made the "duke diya" text Devanāgarī-ish)