I zi.....B-115
II zi ...B
III zi...(B-115)-155
(B-115)+B+[(B-115)-155]=1670
2(B-115)+B-155)=1670
(2B-230+B-155)=1670
(2B+B)-(230+155)=1670
3B-385=1670
3B=1670+385
3B=2055
B=2055:3
B=685
I zi... B-115...........685-115=570
II zi...B..................685
III zi...(B-115)-155...........570-155=415
I+II+III=570+685+415=1670