
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
Professor Tester conducts a series of tests, on the basis of which he assigns the test subject an average score. After finishing the tests, John realized that if he had scored 97 points on the last test, his average score would be 90; and if he had scored only 73 points on the last test, his average score would be 87. How many tests are in Professor Tester's series?

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