A group of people in a city decide to measure the total distance of a walking path and put up distance markers for the people who walk. On one particular day they put up markers on 78 of a mile of the way. The next day they put up markers on another 12 of a mile. What is the total distance they have completed?
To find the total distance, we add the two distances together: 78 + 12 = <<78+12=90>>90.
The group has completed 90 of a mile. Answer: \boxed{90}.