In December she would have saved $1585 because 1235 + 250 = 1485. You can find how much money she raised in those 2 months by adding the totals of both months together, so 1485 + 1235 = 2720. She saved $2720 in the 2 months.
To find the average you would add the three numbers together 169.74+235.95+219.21 to get a total of $624.90 divide that number by 3 to get the average which is $208.30 as the average sale per day