It will cost $100.84 to fill up all four vehicles, and the second month had the higher weekly average over the four weeks by 102 parts.
For the first part of the question regarding the fuel costs, the total mileage for the two mini vans (22 miles per gallon) and the two sport sedans (30 miles per gallon) is 200 miles each. Combining these, the total distance traveled is 800 miles. With fuel costs at $3.20 per gallon, the total cost to fill up all four vehicles is calculated as (800 miles / combined miles per gallon) * cost per gallon, resulting in $100.84.
For the second part of the question, comparing the weekly averages of produced parts in the first and second months, the weekly averages are calculated by dividing the total parts produced in each month by the number of weeks (four weeks in both cases). The first month's weekly average is (10200 + 9630 + 12632 + 10850) / 4 = 10828 parts, and the second month's weekly average is (12423 + 8423 + 14632 + 8150) / 4 = 10707 parts. Therefore, the first month had the higher weekly average, and the difference is 10828 - 10707 = 121 parts. The correct answer is the "first month, 121."