Supplies account balance at March 31st is $680. Supplies expense account balance at March 31st is $960. If the amount in Supplies Expense is the amount of the March 31 adjusting entry, and $780 of supplies were purchased in March what was the balance in Supplies on March 1? (Hint: Prepare the adjusting journal entry for this transaction, post to the Supplies and Supplies Expense T accounts, and work backward to determine the opening balance.)