Question 909150
there are 49 numbers because 49 - 1 + 1 = 48 + 1 = 49


formula for the sum of an arithmetic sequence is n * (a1 + an) / 2


this becomes 49 * (1 + 49) / 2 which becomes 49 * 50 / 2 which becomes 49 * 25 which becomes 1225.


the average is the sum divided by the number of items which becomes 1225 / 49 which becomes 25.


the average is 25.