2. If there are X A-class stations, Y B-class stations, M A-class stations and N B-class stations, there are: 10x+ 15Y.

M+n=30，3m+2n=x，4m+n=y，3m+2n； = 13, m < =17 and m >；; ordinary

So there are two options:

The first scheme is: A has 17 seats, and B has 13 seats.

A has 16 seats and b has 14 seats.