SQL> CREATE TABLE a
  2  (
  3     apofdate   DATE,
  4     apofcode   NUMBER,
  5     city       VARCHAR2 (20),
  6     CONSTRAINT pk_a PRIMARY KEY (apofdate, apofcode)
  7  );

Table created.

SQL> CREATE TABLE b
  2  (
  3     apofdate    DATE,
  4     apofcode    NUMBER,
  5     apofaa      NUMBER,
  6     transport   NUMBER,
  7     CONSTRAINT fk_ba FOREIGN KEY
  8        (apofdate, apofcode)
  9         REFERENCES a (apofdate, apofcode)
 10  );

Table created.

SQL> CREATE TABLE c
  2  (
  3     apofdate         DATE,
  4     apofcode         NUMBER,
  5     apofaa           NUMBER,
  6     perscode         NUMBER,
  7     transport        NUMBER,
  8     transport_cost   NUMBER,
  9     km               NUMBER,
 10     tolls            NUMBER,
 11     CONSTRAINT fk_ca FOREIGN KEY
 12        (apofdate, apofcode)
 13         REFERENCES a (apofdate, apofcode)
 14  );

Table created.

SQL> create or replace trigger trg_ai_b
  2    after insert on b
  3    for each row
  4  begin
  5    insert into c
  6      (apofcode, apofdate, apofaa)
  7    values
  8      (:new.apofcode, :new.apofdate, :new.apofaa);
  9  end;
 10  /

Trigger created.

SQL> insert into a (apofdate, apofcode, city) values
  2    (trunc(sysdate), 1, 'London');

1 row created.

SQL> insert into b (apofdate, apofcode, apofaa, transport) values
  2    (trunc(sysdate), 1, 100, 1000);

1 row created.

SQL> select * from c;

APOFDATE              APOFCODE     APOFAA   PERSCODE  TRANSPORT TRANSPORT_COST         KM      TOLLS
------------------- ---------- ---------- ---------- ---------- -------------- ---------- ----------
10.01.2011 00:00:00          1        100

SQL> select a.apofdate, a.apofcode, c.apofaa
  2  from a, c
  3  where c.apofdate = a.apofdate
  4    and c.apofcode = a.apofcode;

APOFDATE              APOFCODE     APOFAA
------------------- ---------- ----------
10.01.2011 00:00:00          1        100