Question

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

विकल्प

• 17 kg

• 20 kg

• 26 kg

• 31 kg

Answer 1

31 kg

Explanation:
Let A, B and C represent their respective weights.
Then, we have
A + B + C = (45 x 3) = 135                                          ...(i)
A + B = (40 x 2) = 80                                                  ...(ii)
B + C = (43 x 2) = 86                                                ...(iii)
On adding Eqs. (ii) and (iii), we get
A + 2B + C = 166                                                       ...(iv)
On subtracting Eq. (i) from Eq. (iv), we get
B = 31
∴ B's weight = 31 kg