Answer:
Step-by-step explanation:
21st floor + 5 floors = 26th floor
26th floor - 7 floors = 19th floor
19th floor - 6 floors = 13th floor
13th floor + 8 floors = 21st floor
21st floor - 7 floors = 14th floor
14th floor + 7 floors = 21st floor
*** answer is 21st floor***