Question

Average weight of A, B and C is 45 kg. If average weight of A and B is 35 kg and that of B and C is 48 kg. The weight of A is?
1. 39
2. 31
3. 38
4. 42

Answer 1

Correct Answer - Option 1 : 39

Given:

Average of A, B and C = 45 kg

Average of A and B = 35 kg

Average of B and C = 48 kg

Formula used:

Average = Total sum / Total number

Total sum = Average × Total number

Calculation:

Average of A, B and C = 45

∴ 45 = (A + B + C) / 3

∴ A + B + C = 3 × 45 = 135      ----- (1)

Similarly, (A + B) = 2 × 35 = 70      ---- (a)

(B + C) = 2 × 48 = 96

Now, (A + B) + (B + C) = 70 + 96 = 166

∴ A + 2B + C = 166      ---- (2)

⇒ Eqn. (2) – (1)

⇒ (A + 2B + C) – (A + B + C) = 166 – 135 = 31

⇒ B = 31

∴ A = 70 – 31 = 39, from eqn. (a)

Therefore, A = 39