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....... [CLOSED]

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 what is the weight of B?

Answer 1

Average of a, b and c :-
(a+b+c)/3 = 45
a = 135 - (b+c)

Average of a and b :-
(a+b)/2 = 40
a+b = 40*2

Put value of a find above :-
135 - b - c + b = 80
135 - 80 = c
c = 55

Average of b and c :-
(b+c)/2 = 43
b+c = 43*2
b = 86 - c
b = 86 - 55
b = 31

Now, Weight of B :- 31 Kgs

Answer 2

(A+B+C)/3 = 45 (1)
(A+B)/2 = 40 (2)
(B+C)/2 = 43 (3)
Replacing A+B in equation (1)
80 + C = 135 ; C = 55
Replacing C in equation (3)
B = 86 - 55 = 31
The answer is 31