# 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 :

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 :
[A]17 kg
[B]20 kg
[C]26 kg
[D]31 kg

31 kg
Weight of B = (A + B)’s weight + (B + C)’s weight – (A + B + C)’s weight
= 40 $\times$ 2 + 43 $\times$ 2 – 45 $\times$ 3
= 80 + 86 – 135 = 31 kg.
Hence option [D] is correct answer.