20. While reconciling the checking account, an accountant with Sonic Corporation noticed that an error had been made in recording a check received by the company. Sonic recorded the receipt as $729 and the correct amount of the check was $279. What reconciling adjustment is required

You need to deduct $450 from the company's cash balance. Since the check was received from a client, it covered an accounts receivable, so the adjusting entry should be as follows:

XX/YY, adjusting entry to reconcile checking account:

Dr Accounts receivable 450

Cr Cash 450

Accounts receivable and cash both have debit balances, and since you want to increase accounts receivable you must debit it, while you must credit cash in order to decrease it.