The average weight of A, B and C is 45 kg. If the average weight of A ...
Given Information:
The average weight of A, B, and C is 45 kg.
The average weight of A and B is 40 kg.
The average weight of B and C is 43 kg.
Solution:
Let's assume the weight of A, B, and C as A, B, and C kg, respectively.
Step 1: Calculate the sum of weights
The sum of weights of A, B, and C is given by:
A + B + C = (average weight of A, B, and C) * (number of people)
A + B + C = 45 * 3
A + B + C = 135
Step 2: Calculate the sum of weights of A and B
The sum of weights of A and B is given by:
A + B = (average weight of A and B) * (number of people)
A + B = 40 * 2
A + B = 80
Step 3: Calculate the sum of weights of B and C
The sum of weights of B and C is given by:
B + C = (average weight of B and C) * (number of people)
B + C = 43 * 2
B + C = 86
Step 4: Substitute the values in the equations
We can rewrite the equation from Step 1 as:
A = 135 - B - C
Substituting the value of A from Step 4 in the equation from Step 2:
(135 - B - C) + B = 80
135 - C = 80
C = 135 - 80
C = 55
Similarly, substituting the value of C from Step 3 in the equation from Step 4:
A + B = 135 - B - 55
2B = 135 - 55
2B = 80
B = 80/2
B = 40
Therefore, the weight of B is 40 kg.
Answer:
The weight of B is 40 kg, which corresponds to option A.