Assume you are the placement coordinator of a Tier-1 engineering college and it's the first day of placements. Inside the campus, there is a cafe. Estimate how many people have purchased coffee on that particular day.

I will start by a few clarifying questions/ assumptions:
1. We are assuming the 'total coffee purchases' (not just the ones purchased by people involved in placement process).
2. At the coffee cafe, there are multiple food items and beverages sold, but for the sake of this question, we are considering just 'coffee'(hot coffee, capuccino, latte etc). 
3. For sake of convenience, we will count 1 quantity sold = 1 regular cup size(disregarding small, medium, large)

With these out of the way, let's focus on coffee requirements on a regular day. 
Total strength of a tier-1 college = 4*1000(1000 students per year for B.tech) + 250(mtech students) + 50*3(faculty members on campus and their family members) + 100(extra staff/ visitors) == 4000+250+150+100=4500

Assuming half of these drink coffee, and taking 1.5 cup as an average per person(some may drink more, some less, so this should balance out) = 4500/2 * 1.5 = 3500(approx)

Now, since it is placement day 1:

1. All the final year Btech students will be sitting for the process(no one has been hired yet, so as to be not sitting for placements) = 1000 students
2. Hiring members from companies visit the campus(50 people)

Assuming that everyone involved has to put in extra hours, stay active, perhaps be at placement department till late night, we can assume the coffee consumption for people involved doubles, and out of those who didn't drink coffee earlier, 75% drink one cup
Therefore: (1000/2)*0.75 + (1000/2)*1.5 + 50*1.5 = 325+750+75 = 1200(approx)

So total coffee servings consumed on day 1 = 3500+1200 = 4700 servings of regualr sized cups

Here's how I would go about answering this question:

1. I will first of all assume there are 50 tables in the coffee cafe.

2. Each table seats 4 people and I will assume there's only one paying member on a table.

3. Since it's the first day of placements I will assume there will be a 80% occupancy throughout the day which means 40 tables are occupied at any time of the day. 

4. Let's assume total time spent on a table to be 30 minutes.

5. Total number of paying members (considering there's only one paying member on a table) in an hour based on 3) and 4) would be 80. 

6. Assuming the college is open for 8 hrs in a day, the total number of people who have purchased coffee in a day (80 x 8) = 640

7. Total Number of Coffees purchased at an average of 3 members per table would 640*3 = 1920 ~ 2000 (Approximately)