City code says you need to have a total of at least 54 toilet stalls, but each bathroom can only have 6 stalls.
So, Let the number of bathrooms to be built be = x
Number of toilet stalls needed = 54
Number of stalls each bathroom can have = 6
So, the number of bathrooms to be built are =
![6(x)=54](https://img.qammunity.org/2019/formulas/mathematics/high-school/j7743gwwl44uz0rm3webncxquib612wiko.png)
![x=(54)/(6)](https://img.qammunity.org/2019/formulas/mathematics/high-school/qrlldtkd5flposmiguwo2pglv8k7sw3g8z.png)
![x=9](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ezy49ncjj6m8dvz4krr9ok07ir3u3k8oz9.png)
Hence, one must build 9 bathrooms with 6 stalls each.