Multiple choice

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:

  1. 31 kg

  2. 32 kg

  3. 29.5 kg

  4. 35 kg
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A+B+C = 45*3 = 135. A+B = 40*2 = 80. B+C = 43*2 = 86. (A+B) + (B+C) = 80 + 86 = 166. (A+B+C) + B = 166. 135 + B = 166, so B = 31.

AI explanation

The combined weight of A, B, and C is 3 times 45 kg, which equals 135 kg. The combined weight of A and B is 2 times 40 kg, giving 80 kg, and the combined weight of B and C is 2 times 43 kg, giving 86 kg. Adding the weights of (A plus B) and (B plus C) results in 80 plus 86, which equals 166 kg. Subtracting the total weight of A, B, and C from this sum leaves the weight of B, so 166 minus 135 equals 31 kg.

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