Essays / Essay for internship with a business school (word limit / essay kind / advice?) [2]

Hi,
I am BSc Maths hons student (although i have courses in maths, computers, economics and statistics) with an MBA in Finance as my upcoming post graduate course but as you know MBA requires work experience and if that comes as a summer internship with a reputed management institute my chances of acceptance automatically increase. Now the thing is I have to write an essay for internship with IIM-Ahemdabad.

The topic is

Have you ever worked on an internet marketing or social media marketing project? (no word limit)

My doubt is-
1. What word limit should I adhere to? (200-250 is rit?)
2. What kind of essay should it be?
3. Any general piece of advice

Thanks in advance