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    Question

    The average weight of A, B and C is 45 kg. If the

    average weight of A and B be 40 kg andthat of B and C be 43 kg, then the weight of B is :
    A 31 kg Correct Answer Incorrect Answer
    B 32 kg Correct Answer Incorrect Answer
    C 29.5kg Correct Answer Incorrect Answer
    D 35 kg Correct Answer Incorrect Answer

    Solution

    average weight of A, B and C is 45 kg (A+B+C)/3 = 45 A+B+C = 45 × 3 = 135 the average weight of A and B is 40 kg (A+B)/2 = 40 A+B = 40 × 2 = 80 the average weight of B and C is 43 kg (B+C)/2 = 43 B+C = 43 × 2 = 86 Adding A+B + B+C = 80 + 86 = 166 Subtracting A+B+C from this we get 166-135 = 31 B = 31kg

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