What is the approximate difference between the average number of people working in Marketing and production departments from all the organisations together?

Total number of employees working in Marketing department = 1382 + 1384 + 1275 + 1300 + 1290 = 6631
Total number of employees working in production department = 1542 + 1545 + 1550 + 1570 + 1580 = 7787
Their difference = 77 - 6631 = 1156
Hence, average difference = 1156/5 = 231.2 ≈ 231