[ Average values $]$

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

#
A change of 24 points in the score changes the average by 3 points. This means there are $24 : 3 = 8$ tests.

## Answer

8 tests.

## Problem