Explanation:

To find out the required sales on the 6th day to reach an average of Rs8,500 across six days, you need to do the following calculations:

- First, calculate the total sales for the first five days: Rs5,000 + Rs6,000 + Rs8,000 + Rs7,000 + Rs9,000 = Rs35,000.

- To find the total sales needed for six days with an average of Rs8,500, multiply Rs8,500 (desired average) by 6 (total days): Rs8,500 x 6 = Rs51,000.

- Subtract the total of the first five days' sales from the total needed: Rs51,000 - Rs35,000 = Rs16,000.

- Therefore, the sales must be Rs16,000 on the 6th day.

Options:

- Option 1: Rs16,000 - This is correct.

- Option 2: Rs12,000 - This would lead to a lower average.

- Option 3: Rs15,000 - This would also lead to a lower average.

- Option 4: Rs10,000 - This would lead to a much lower average.

Option 1: Rs16,000 is the correct choice.

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