Question

If average weight of A, B and C is 45 kg. If the average weight of A and B is 40 kg and that of B and C be 43 kg, then what is the weight of B?

Answer 1

(A+B+C)/3=45kg
=>[(A+B)+C]=135kg..................................(i)
(A+B)/2=40kg
(A+B)=80kg.............................................(ii)
(B+C)/2=43kg
=>C=86-B..............................................(iii)
Now,
[(A+B)+C]=135
[(80)+(86-B)]=135.............put values from (ii)& (iii) into (i)
B=31kg
Ans weight of B is 31 kg

Answer 2

• (A+B+C) / 3 = 45
• (A+B) / 2 = 40
• ( B+C) / 2 = 43
  Solve the sytem of equations
  If (A + B ) = 80, 80+ C = 45 * 3 , C = 55
  Then B + 55 = 43 * 2 , B = 31

Solution B= 31