Explanation

The first 10 even numbers in ascending order are:

{2, 4, 6, 8, 10, 12, 14, 16, 18, 20}.

Average formula:

Average= (Sum of observations)(Number of Observations)

Average = (2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18 + 20 ) / 10 

Average = 110/10 

Average = 11