The average weight of 3 men A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E, whose weight is 3 kg more than that of D, replaces A then the average weight of B, C, D and E becomes 79 kg. The weight of A is :

a. 70 kg
b. 72 kg
c. 75 kg
d. 80 kg

• A+B+C=84*3=252....(i)
  A+B+C+D=80*4=320...(ii)
  D's age = 320-252=68 kg
  then E's age = 68+3=71 kg
  Now, B+C+D+E = 79*4=316.....(iii) B+C+68+71=316 or B+C = 177.....(iv)
  Put value of B+C in eqn (i)
  A=252-177 = 75kg Ans.
  
• 9 years agoHelpfull: Yes(4) No(1)
• A+B+C=252
  A+B+C+D=320
  SOLVING WE GET
  D=320-252=68 AND E=68+3=71
  B+C+D+E=316
  SOLVING WE GET
  A-E=4
  A=75
• 6 years agoHelpfull: Yes(0) No(0)
• (A+B+C)/3=84
  A+B+C=252 1
  (A+B+C+D)/4=80
  A+B+c+D=320 2
  BY SOLVING EQN 1 AND 2 D=68
  (B+C+D+E)/4=79
  B+C+D+E=316
  WHEN D=68 THEN E=71
  B+C=177 3
  BY SOLVING EQN 1 AND 3
  A=75 KG
• 5 years agoHelpfull: Yes(0) No(0)
• see other solutions, but check calculations yourself, instead of 75, its 79
• 4 years agoHelpfull: Yes(0) No(0)
• 1.A+B+C=84*3
  2.A+B+C+D=80*4
  3.B+C+D+E=79*4
  SOLVING FIRST AND SECOND eq D=68
  E=68+3=71
  FROM 3RD B+C+D= 245
  FROM SECOND EQ A=320-(B+C+D)=75
• 4 years agoHelpfull: Yes(0) No(0)