
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
A professor conducts a series of tests and assigns an average score to the test-takers. John realizes that if he had scored 97 on the last test, his average score would have been 90. On the other hand, if he had scored only 73 on the last test, his average score would still have been 87. How many tests are in the professor's series?

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