A ,B and C average is 45 ,b and C average is 40 then find b

This question is incomplete

Complete 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 :

31 kg

Step-by-step explanation:

From the above question:

A ,B and C average is 45.

Hence, the total values of A, B, C is calculated as:

A + B + C /3 = 45

A + B + C = 45 × 3

A + B + C = 135

Also,

B and C average is 43

The total values of B, C is calculated as:

B + C /2 = 43

B + C = 43 × 2

B + C = 86

A and B average is 40

The total values of A, B is calculated as:

A + B /2 = 40

A + B = 40 × 2

A + B = 80

Hence:

A + B + C = 135

B + C = 86

A + B = 80

Hence, we can solve for A, we substitute 80 for A + B

80 + C = 135

C = 135 - 80

C = 55kg

B + C = 86

B + 55 = 86

B = 86 - 55

B = 31 kg