the average weight of 5 men is decreased by 3 kg when one of them weighting 150kg is replaced by another person.this new person is again replaced by another person whose weight is 30 kg lower than the person he replaced..what is the overall change in the average due to this dual change.

• When one of them is replaced by one person weighting 150 average weight is decreased by 3 kg so new person's weight is (150-3*5)=135 kg.Again he is replaced by another person whose weight is 30 kg less. So average weight is decreased by 30/5=6 kg .Total average weight is decreased by (3+6)=9 kg.
• 8 years agoHelpfull: Yes(2) No(0)
• (sum of weight of 5 men)/5=average weight of 5 men (x)
  sum of wt. of 5 men =5x
  let the wt. of new men =y
  acc to q
  {(sum of wt. of 5 men -150+y)/5}=x-3
  5x-150+y=5x-15
  y=135
  z=105 (weight of another person which come in place of new person i.e 135-30=105)
  (sum of wt. of 5 person -135+105)/5=M(new average)
  5x-30=5M
  x-M=30/5
  x-M=6 (ans)
• 9 years agoHelpfull: Yes(1) No(5)
• Let average weight of 5 men be A..... Of these 5,the one weighing 150kg is replaced by another person first ...let sum of weights of the other 4 be S4....
  we can write average as,
  (S4+150)/5=A
  Let the weight of new person be W5.... Average is decreased by 3kg....
  So we can write,
  (S4+W5)/5=A-3
  The person with weight W5 is replaced by a person with weight W5-30....
  We can write equation for average as,
  (S4+W5-30)/5=(S4+W5)/5 - (30/5) =(A-3) -(6)= A-9
  => overall change in average is 9kg (9kg lower than original average)
• 8 years agoHelpfull: Yes(1) No(0)
• average is decreased by 9.
  let the weight of replaced person is d, and prev average is x
  5x-150+d=5(x-3)
  d=135.
  
  5x-150+105=5t
  therefore,
  t=x-9
  
  
• 8 years agoHelpfull: Yes(0) No(0)