The average weight of A, B and C is 77 kg. If the average weight of A and B is 68 kg and that of B and C is 83 kg, then the weight (in kg) of B is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 71.
We know that,
Average = sum of observations/total number of observations
Now,
Sum of weights of A, B and C = 77 × 3 = 231 ---- (1)
Sum of weights of A and B = 68 × 2 = 136
Sum of weights of B and C = 83 × 2 = 166
According to the question;
⇒ A + B + B + C = 136 + 166 = 302 ---- (2)
Now equating (2) - (1), we get
⇒ (A + 2B + C) - (A + B + C) = 302 - 231
⇒ B = 71 kg