Answer:
A = (166+s)/3
Step-by-step explanation:
Average test-score:
Sum of all scores divided by the number of tests.
In this question:
First two tests: 77 and 89.
Third test: s
Number of tests: 3
Average:
Finding the sum: 77 + 89 + s = 166 + s
The average is:
A = (166+s)/3
