Final answer:
The adjusting journal entry required at year-end includes a debit to supplies expense $700 and a credit to supplies on hand $700.
Step-by-step explanation:
The adjusting journal entry required at year-end includes a debit to supplies expense $700 and a credit to supplies on hand $700. These entries are necessary to decrease the asset account for supplies on hand and record the expense of the supplies that were used during the year. The remaining supplies worth $300 will be accounted for in the ending inventory.