Bank Reconciliation Adjustment Steps:

• Identify cash book balance as $20 debit (positive bank balance per trader's records).
• Recognize "cheque not yet presented $80" as unpresented payment: add$80 to cash book since bank hasn't deducted it.
• Recognize "cheque not credited $470" as uncleared deposit: subtract$470 from cash book since bank hasn't added it.
• Calculate adjusted balance: $20 +$80 - $470 = -$370 (overdraft), but options don't match and term "not credited" lacks clarity on whether it's a receipt or payment.

Not enough information.

Final answer: Not enough information.