Question 1192223
<br>
For problems about the average of a group of numbers that are close together, it is often faster to find the answer by choosing an estimated average and looking at the "overs" and "unders" of the individual tests.<br>
These test scores are all close to 80, so assume an average of 80 and look at the overs and unders.  The final counts as three tests, so count the score on the final three times.<br>
85: +5
76: -4
82: +2
79: -1
79: -1
79: -1
-------
sum: 0<br>
The "overs" and "unders" exactly cancel each other, showing that the average is exactly 80.<br>