You can put this solution on YOUR website! average is total divided by number of trials
the total is 257, the sum of the 3
Divide by 3, and average is 85 2/3.
Check
The first is 7 2/3 below the average
The second is 2/3 below the average. Their total is 8 1/3
The third is 8 1/3 above the average which balances.