Answer:
The answer is: record a $400 debit on accounts payable and a $400 credit on merchandise inventory
Explanation:
The buyer should record a debit on accounts payable for $400, and should record a credit for merchandise inventory for $400.
Accounts payable is a liability, so when you record a debit, you are decreasing it.
Merchandise inventory is a current asset, so when you record a credit, you are decreasing it.