How long are essays?
To be honest, it's not the quantity you write, its the quality of your writing in the essay.
Even if you write 2 pages, and it conveys the question being asked then you would still receive the top mark.
For example, If someone did 10 pages load of crap, and you did 2 pages related to the question, who is going to gain the top marks? You who did 2 pages or that person who did 10 pages?
Indeed you, so don't worry about how long your essays have too be. It's quality not quantity that counts.