I won't take the job. Try a public uni, there you will get away with about 14 - 16 classes a week for more or less the same salary!

Salaries at public universities in China usually go from 4000 to 5000/month for 14-16 teaching hours/week. There is the occasional one offering as low as 3500/month at the low end, and 6000/month at the high end. Most offer 4500 or 5000 a month. Figures are in RMB