Answer:
11
Step-by-step explanation:
To do this you would just multiply 9 by 3 so you get 27 and subtract 6+10 which is 16 from it and then you will get 11 and that is what you will need for your third score
The third score which must be added is 11.
The average can be calculated by dividing the sum of observations by the number of observations.
Average = Sum of observations/the number of observations
Given; count = 3 (there are three trials)
average = 9
9 = sum / 3
The sum = first score + second score + third score
The sum = 6 + 10 + third score
9 = (6+10+third score)/3
Then multiply both sides by 3 to remove the denominator
27 = 6 + 10 + third score
27 = 16 + third score
Now, subtract 16 from both sides to isolate the third score
11 = third score
Hence, the third score which must be added is 11.
Learn more about average here;
https://brainly.com/question/27851466
#SPJ2
