x-

1

5

x-8-[（x-

1

5

x-8）×

1

3

-4]=124
            

4

5

x-8-[

4

15

x-

8

3

-4]=124
               

4

5

x-8-

4

15

x-1

1

3

=124
                        

8

15

x=133

1

3

                            x=750
答：两地相距750千米．