1. With price discrimination
Domestic market Qd = 21-0.1Pd
    Pd 
                                


           D=AR
        MR                S
Pd*=110




           Qd*=10                  Qd

foreign market: 50-0.4Pf
    Pf 
                                


         D=AR
                          S
         MR 
Pf*=67.5



           Qd*=23                  Qf

2. Without price discrimination
The whole market: Q = 71-0.5P
    P 
                                


           D=AR
        MR                   S
P*=76




           Qd*=33                  Q