The following summarizes the aging of accounts receivable for Johnston Supplies, Inc. as of December 31, 2020:

Number of Days Unpaid	Total Accounts Receivable			Historical % Uncollectible
Not yet due	$	126,500			2	%
1-30 days past due		89,200			12	%
31-60 days past due		53,600			18	%
Over 60 days past due		31,800			35	%

Required:

1. The unadjusted balance of the Allowance for Doubtful Accounts of Johnston Supplies, Inc. is a credit balance in the amount of $8,947 on January 1, 2020. Prepare the required adjusting entry to record Bad Debt Expense on December 31, 2020.

2. If Johnston Supplies, Inc. writes off $4,081 of uncollectible accounts on January 21, 2021. Prepare the required adjusting entry to record the write-off.

3. What is the net accounts receivable balance after the adjusting entry was made on January 21, 2021?

4. Why does Johnson Supplies Inc. have to adjust for bad debt expenses?