What will be the Weight of B? If

The average weight of A,B,C is 45 kg. If the average weight of A  and B is 40 kg and that of Band C is 43 kg. then the weight of B is:

  1. 17 kg
  2. 20 kg
  3. 26 kg
  4. 31 kg
Nitin Baudh Learner Asked on 29th July 2015 in Maths.
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  • 1 Answer(s)

    Answer: (4)  31 kg
    Explanation:-
    The average weight of A, B  & C  = 45 kg.
    Then, the total weight of A, B & C = 45 x 3
    = 135 kg.
    A + B + C = 135  …………………………………………….. (1)

    The average weight of A & B = 40 kg
    Then, the total weight of A & B = 2 x 40
    = 80 kg.
    or A + B = 80                                ……………………….  (2)

    The average weight of B  & C = 43 kg
    Then, the average of B & C = 43 x 2
    = 86 kg.
    or B + C = 86                         ……………………………………. (3)

    Adding equation (2) & (3),
    A + B + B + C = 80 + 86
    A + 2 B + C = 166 ……………………………………………. (4)

    Subtracting equation (1) from (4)
    Then, (A + 2 B + C) – (A + B + C) = 166 – 135
    B = 31 kg.
    Hence, the weight of B is (4) 31 kg.

    Anurag Mishra Professor Answered on 29th July 2015.
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