Can I get some help and explanations in solving these please.

MC4-21. L A city government started its fiscal year with a fund balance of $18,000. At the end of the year, its accounts showed the following items: estimated revenues$600,000; appropriations$580,000; actual revenues$570,000; actual expenditures$576,000. How much was the city's fund balance after it closed its accounts? a. $12,000 b. $24,000 c. $32,000 d. $38,000 MC4-22. A local government appropriated $100,000 for supplies for its police department. Two purchase orders were placed: PO A for $50,000 and PO B for $30,000. Supplies ordered on PO A were received but, because of a price reduction, the invoice was for $48,000. The invoice was paid. Supplies ordered on PO B have not yet been received. How much of the $100,000 appropriation is available for spending? a. $18,000 b. $20,000 c. $22,000 d. $48,000