Bank reconciliation requires both cash book and bank statement balances to determine unpresented cheques Steps:

• Note cash book balance of $760 (debit, positive).
• Adjust for bank charges $90: subtract from cash book as unrecorded debit by bank (adjusted =$760 - $90 =$670).
• Adjust for dishonoured cheque $120: subtract from cash book as unrecorded reversal of deposit (adjusted =$670 - 550).
• To find unpresented cheques, subtract adjusted cash book from bank statement balance (assuming no lodgements in transit); bank statement balance not provided. Not enough information.

Final answer: Not enough information.