Hi, I am having a very hard time doing the following, can anyone help?

On December 31, 2011 the unadjusted trail balance of Alex Inc., included the following accounts:

debit credit

Sales (90% represent credit sales) 900,000

accounts receivable 300,000

allowance for doubtful accounts 300

1. Assume Alex estimates bad debts expense as 1% of credit sales. Prepare the adjusting entry for bad debts on December 31.
2. Instead of #1, assume Alex estimates bad debts expense as 3% of year end gross accounts receivable. Prepare the adjusting entry for bad debts on 12/3/2011.
3. Based on your answer in #2 assume Alex estimates bad debts expense as 3% of year end gross accounts receivable After the adjusting entry, the net realizable value of Alex's accounts receivable in the Dec. 31, 2011 balance sheet is : $_______________________
4. Based on you answer to number 2 Alex writes off an uncollectible customer account on 1/8/12 in the amount of $800, prepare the journal entry to write off the uncollectible account receivable.
5. based on your answer in4 after the entry to write off the account receivable on 1/8/12 the net realizable value of Alex's accounts receivables in the 1/8/12 balance sheet is $_________