The mean of 100 bags was found to be 30. What will be the correct
mean
if at the time of calculation two bags were wrongly taken as 32 and 12
instead of 23 and 11?
A. 29.9
B. 30.5
C. 34.9
D. 50.8

• mean=total sum/total no.
  total sum==30*100=3000;
  total no.==100
  now by mistake take==32,12.....(32+12=44)
  sub. with total==3000-44=2956
  now use correction==2956+(23+11)=2990
  mean=2990/100=29.9 (A)
• 9 years agoHelpfull: Yes(43) No(1)
• 100*30=3000
  44-34=10
  3000-10=2990
  2990/100=29.9
• 9 years agoHelpfull: Yes(18) No(0)
• net difference is (23-32)+(11-12)=-10
  so, actual mean = 30+(-10)/100=29.9
• 9 years agoHelpfull: Yes(4) No(0)
• (98x+32+12)/100=30.
  So 98x=2956
  Now (98x+23+11)/100=(2956+23+11)/100=29.9
  The second way to solve this problem is to think logically. As the weight of the bags reduced, mean should also reduce. The only number which is less than 30 is 29.9 in the options. So ans is 29.9
• 9 years agoHelpfull: Yes(3) No(0)
• Formula
  New Average = Old Average - (Changes in calculation/Total number of bags)
  Changes in calculation =>
  (32+12) - (23+11) = 10
  Total number of bags = 100
  
  Therefore,, New Average = 30 - (10/100)
  
  On solving the answer is 29.9
  
  This is simple and easy method
• 4 years agoHelpfull: Yes(3) No(0)
• sum of the bags=30*100=3000
  now it said that (32+12)is wrongly taken instead of (23+11) so new mean will be=3000-44+34/100
  2990/100=29.9ans
• 9 years agoHelpfull: Yes(1) No(1)
• shortcut method:
  correct answer: 29.9
  given avg of 100 bag=30
  by mistake he take 32 and 12 instead of 23 and 11
  so gap 9+1=10 more in 100 bag so one bag=0.1
  so avg is decrease 30-0.1=29.9 is correct answer.
  
  
  
• 8 years agoHelpfull: Yes(1) No(0)
• sum = 30*100 =3000
  32 and 12 is calculated wrongly as 23 and 11 should be there ,so we will subtract 32 and 21 from the sum which gives 3000 - (32 + 12) =2958
  now add 23 and 11 in 2958 which gives 2992 which is sum .
  mean =sum /no.
  so mean is 2992/100 =29.92 which is a part
  
• 9 years agoHelpfull: Yes(0) No(4)
• sum=3000;
  3000-48=2592
  2592+34=2986
  2986/100=29.9
• 8 years agoHelpfull: Yes(0) No(1)
• 2990/100=29.9
• 6 years agoHelpfull: Yes(0) No(0)
• As we have given mean and n
  therefore we have to take out the sum of all the observations(x)
  that is
  x = mean × n
  x= 30 ×100
  x = 3000
  now add the correct no. which were misread that is
  add 23 and 11
  and you will get
  3034
  now subtract the wrong no. that is
  sub 32 and 12 from 3034
  that will give you 2990
  now it is your new sum of observations
  therefore new mean will be
  2990/100
  =29.9
• 6 years agoHelpfull: Yes(0) No(0)
• mean of 100=30
  incorrect nos.=32 instead of 23 and 12 instead of 11
  -32+23-12+11/100=-10/100=-0.1
  30-0.1=29.9
• 6 years agoHelpfull: Yes(0) No(0)
• X+32+12/100=30
  X=2956
  2956+23+11/100=29.9
• 4 years agoHelpfull: Yes(0) No(0)