Answer:
The apartment with the number 207 is in the second floor of the building that comes before the building with apartments numbered 109, 110, 111, and 112
Step-by-step explanation:
The given information of the naming of the apartments are;
The four apartments on the first floor of the building were numbered, 109, 110, 111, and 112
Therefore;
The first digit number, 1, which is consistent, represent the floor number (first floor)
The buildings in the complex are 9-story buildings, with 9 × 4 = 36 Apartments each
Therefore, for the numbers of the apartment to be from 9 to 12, on the floor, the numbering of the apartments is sideways such that the numbers of the apartment in the given building will be X09, X10, X11, and X12, where X is the floor number
The previous building apartment will be numbered X05, X06, X07, X08
Therefore, the apartment with the number 207 is in the second floor of the previous building to the one given.