Maxwell Inc. analyzed its accounts receivable balances at December 31, and arrived at the aged balances listed below, along with the percentage that is estimated to be uncollectible:

		% Considered
Age Group	Balance	Uncollectible
0-30 days past due	$100,000	1%
31-60 days past due	18,000	3%
61-120 days past due	20,000	6%
121-180 days past due	7,000	10%
Over 180 days past due	2,000	20%
	$147,000

The company handles credit losses using the allowance method. The credit balance of the Allowance for Doubtful Accounts is $840 on December 31, before any adjustments. a. Determine the amount of the adjustment for estimated credit losses on December 31. $Answer b. Determine the financial statement effect of a write off of Porter Companys account on the following May 12, in the amount of $480. Use negative signs with answers, when appropriate. If a transaction increases and decreases the same Balance Sheet category, enter the increase amount in the first row and the decrease amount directly below (in the second row).

Balance Sheet								Income Statement
				Stockholders'
Assets	=	Liabilities	+	Equity				Revenues	-	Expenses	=	Net Income