Answer:
March 31, outstanding debt $25,000
During April $10,000 more merchandise is sold to Cars inc. (COGS $8,000)
Cars paid $12,000 to Preston to lower its accounts payable
On March 31, Preston's balance sheet showed an accounts receivable of $25,000.
On April 30, the accounts receivable balance is $23,000, the cash balance increased by $12,000 and retained earnings should increase by $2,000.
The income statement should show an increases in sales revenue of $10,000 - $8,000 COGS = $2,000 profit (which increases retained earnings).