Im doing a business preject for Economics... and im supposed to find out how much it would cost to open a bar. so can anyone please tell me the aprox. amount of money i would need to open a bar. :/

Well start using your noggin. I'll help get you started:

Rent, a few thousand per month
Utilities (figure out which ones and how much)
Payroll (how many employees and how much would you pay them?)
Advertising (research the type and costs)
Signage (google some sign co's)
Permits/Licenses
Attorney/Accountant fees
Equipment/Supplies (this one will take a while for you to research...google a restaurant supply wholesaler...guess how many tables, chairs, glassware, etc you might need and figure the costs)

This should give you a good head start. I'm not doing all your homeework for you!