How do I know if its enough $$? (Guangzhou)

Hello all, I have been offered a job in Sierra Leone (Africa), Beijing and Guangzhou. I don't know which one I should take.

I need an option about how much money a family of 3 (husband, wife, and 3 yr old) plus 2 dogs need. I know its a random and a wide open answer.

But as of right now, we live in Cairo, Egypt. We rent a 2 bedroom (90m) apt for $300 usd a month. Utilities here are basically nothing. My son goes to school for free (I'm a teacher) and we spend about $430 a month in groceries. We don't go out that often so typically we don't spend more than $150 a month in dinning out.

I want to keep our life basically the same. What is the salary we would need to make (TOTAL NUMBER) to make it work?

Thanks for your help!!