52, 54, 56, … 616, 618, 620
Above is the set of consecutive even integers from 52 to 620, inclusive.
How do you find the average of this set (or any set of terms that are equally-spaced by addition)?
Instead of dividing the sum of all terms by the count (the number of terms), just average the first and last terms.
So, average = (first + last) / 2.
For the set above, the average is (52 + 620)/2 = 336.
Happy prepping! 😎
Ren