
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
When the purchase price of a product is 40 yuan and it is sold for 50 yuan, 500 units can be sold. It is known that for every 1 yuan increase in price, the sales volume decreases by 10 units. To achieve a profit of 8000 yuan, while keeping the cost no higher than 10000 yuan, what should the selling price be? And how many units should be purchased at that time?

Present the answer in LaTex format: \boxed{Your answer}
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