Tad was delivering lunch to a local office building. His first delivery was to the middle floor of the building. He then took th elevator up 4 floors for the next delivery, down 6 floors for his third delivery, and up 7 floors for his final delivery. He was then on the top floor of the building. How many floors were in this building?

x+4-6+7= 5

5+5=10

To find the number of floors in the building, we can start by taking the first delivery floor as a reference point and then add or subtract the number of floors Tad went up or down for each subsequent delivery.

Let's denote the first delivery floor as x.

- Tad went up 4 floors from the first delivery floor, so we can add 4: x + 4.
- Next, he went down 6 floors, so we subtract 6 from the previous result: (x + 4) - 6 = x - 2.
- Finally, Tad went up 7 floors, so we add 7 to the previous result: (x - 2) + 7 = x + 5.

Since Tad ended up on the top floor after his final delivery, we can conclude that the number of floors in the building is x + 5.

Therefore, we need to determine the value of x.

Unfortunately, the information provided in the question is not sufficient to determine the exact value of x or the number of floors in the building. We only know Tad's movement between the floors, but not the initial floor or the total number of floors in the building.