Can you help me?

Two sisters recently opened a truck repair garage in Alberta. Alberta does not participate in the HST program and does not have a provincial sales tax. They have asked you to calculate the GST payable or refund for the first reporting period. Given the following information: Sales $ 80,000, Equipment purchased 100,000, Supplies purchased 50,000, Wages paid 20,000 and Rent paid 6,400. What should the garages GST payable or refund be (all amounts are before GST; sales are fully taxable, and expenditures are used for the provision of fully taxable supplies)?

		A refund of $3,820.
		A refund of $3,500.
		A refund of $4,820.
		A payable of $180.