Need help with the following:

1. At January 1, 2008, Kobe Enterprises reported accounts receivable totaling $3,500. During the month, the company had credit sales of $5,000 and collected cash on accounts of $6,000. At the end of January, the balance in accounts receivable is:

2. At January 1, 2009, KA Enterprises reported an accounts payable of $5,000. During the month, KA made purchase on account from vendors totaling $7,000. At the end of January, the balance in accounts payable is $8,000. What amount did KA pay vendors during January?

3. At January 1, 2007, Burton Industries reported Retained Earnings of $130,000. During 2007, Burton had a net loss of $30,000 and paid dividends to the stockholders of $20,000. At December 31, 2007, the balance in Retained Earnings is:

4. Fisher Enterprises assets increased from $7,000 to $9,000, and liabilities decreased from $3,000 to $1,500. Assuming no additional owners equity transactions took place, if expenses totaled $3,000, what was Fisher's revenue for the year?