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, what is the weight of B? Choose one
A) 31 kg  B) 28 1/2 kg  C) 32 kg  D) 30 1/2 kg  E) 32 kg
Explanation:   Let the weight of A, B and C are a,b and c respectively.   31 kgverage weight of 31 kg,B and C = 45   a + b + c = 45 × 3 = 135 --- equation(1)   31 kgverage weight of 31 kg and B = 40   a + b = 40 × 2 = 80 --- equation(2)   31 kgverage weight of B and C = 43   b + c = 43 × 2 = 86 --- equation(3)   equation(2) + equation(3) - equation(1)   =&gt; a + b + b + c - (a + b + c) = 80 + 86 - 135   =&gt; b = 80 + 86 -135 = 166 - 135= 
<gadget id="calculator">166 - 135</gadget>
<output>31</output>
31   Weight of B= 31 Kg   31 kgnswer: Option 31 kg
<result>A</result>
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, what is the weight of B?