# What will be the Weight of B? If

The average weight of A,B,C is 45 kg. If the average weight of A and B is 40 kg and that of Band C is 43 kg. then the weight of B is:

- 17 kg
- 20 kg
- 26 kg
- 31 kg

**Answer: (4) 31 kg**

**Explanation:-**

The average weight of A, B & C = 45 kg.

Then, the total weight of A, B & C = 45 x 3

= 135 kg.

A + B + C = 135 …………………………………………….. (1)

The average weight of A & B = 40 kg

Then, the total weight of A & B = 2 x 40

= 80 kg.

or A + B = 80 ………………………. (2)

The average weight of B & C = 43 kg

Then, the average of B & C = 43 x 2

= 86 kg.

or B + C = 86 ……………………………………. (3)

Adding equation (2) & (3),

A + B + B + C = 80 + 86

A + 2 B + C = 166 ……………………………………………. (4)

Subtracting equation (1) from (4)

Then, (A + 2 B + C) – (A + B + C) = 166 – 135

B = 31 kg.

Hence, the weight of B is (4) 31 kg.