Why are there 51, square meters and 31, square meters of second-hand houses in Zhonghao Century Garden?

First of all, these two are different in nature. One is a mansion, which is used for commercial and residential purposes, and the other is a residence. Second, these two property rights are different. One is a 4-year property right, the other is a 5-year property right, and the location is different. One is on the side of the road, which acts as an office building or something. It is usually noisy, and there are eight or nine households on each floor. The other is inside, and the environment is relatively quiet. Finally, they are all primary school districts attached to the Second Division.