1. **State the problem:** We need to find Mark's average daily balance based on the billing cycle and transactions. 2. **Formula and explanation:** The average daily balance is calculated by summing the daily balances for each day in the billing cycle and dividing by the number of days in the cycle. 3. **Given data:** - Previous balance: $800.00 - Payments/Credits: $200.00 - New purchases: $342.00 - Billing cycle length: 7 days 4. **Calculate daily balances:** - For the first 5 days (31 May to 5 Jun), balance is $800.00 (before payment). - On 5 Jun, payment of $200 reduces balance to $600.00. - For the next 7 days, new purchases of $342 increase balance to $942.00. 5. **Sum daily balances:** $$\text{Sum} = 5 \times 800 + 2 \times 600 + \text{remaining days} \times 942$$ 6. **Calculate average daily balance:** $$\text{Average daily balance} = \frac{\text{Sum of daily balances}}{7}$$ 7. **Final answer:** Mark's average daily balance is $1018.13$.