The average weight of A, B and C is 45 Kg, If the average weight of A and B be 40 Kg and that of B and C be 43 Kg then the weight of B is:

Total Weight of A,B & C = 45
Weight of Single One = 45*3=135
Total Weight of A & B = 40
Weight of Single One = 40.*2=80
Total weight of B & C = 43
Weight of Single One = 43*2=86
A + B + C = 135
80+C=135
C=135-80=55
B+C = 86
B+55=86