(3/11)s=s1(7/20)(s-3/11s)=s2(7/20)(8/11)s=s2(14/55)s=s2(5/13)(s-(3/11)s-(14/55)s)=s3(2/11)s=s3S=s1+s2+s3+320s-(s1+s2+s3+320)=0s-(3/11)s-(14/55)s-(2/11)s-320=0(6/11)s-(14/55)s-320=0(16/55)s=320s=20*55=1100км
(3/11)s=s1
(7/20)(s-3/11s)=s2
(7/20)(8/11)s=s2
(14/55)s=s2
(5/13)(s-(3/11)s-(14/55)s)=s3
(2/11)s=s3
S=s1+s2+s3+320
s-(s1+s2+s3+320)=0
s-(3/11)s-(14/55)s-(2/11)s-320=0
(6/11)s-(14/55)s-320=0
(16/55)s=320
s=20*55=1100км