Aptitude - Average - Discussion
Discussion Forum : Average - General Questions (Q.No. 5)
5.
The average weight of 8 person's increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. What might be the weight of the new person?
Answer: Option
Explanation:
Total weight increased = (8 x 2.5) kg = 20 kg.
Weight of new person = (65 + 20) kg = 85 kg.
Video Explanation: https://youtu.be/ceg2jvHsiJU
Discussion:
85 comments Page 6 of 9.
Saravanan said:
1 decade ago
Replaced value+(Increase in average*Total number of observation).
Manoj Kumar said:
1 decade ago
Thanks for your support guys. Will post more useful information in future.
Sneha said:
1 decade ago
@Manoj Kumar Sir, your tricks are really useful.
Fakhar said:
1 decade ago
I am totally confused. Can any one give me solution?
Sarvesg said:
1 decade ago
The first line says average weight weight of person is increased by 2.5.
1) So the total weight increase is = 2.5*8 = 20.
2) Then it says when old person weighting 65 kg is replaced by new one since the weight increase is because of only one person add the old person weight+the average weight = 65+20 = 85.
1) So the total weight increase is = 2.5*8 = 20.
2) Then it says when old person weighting 65 kg is replaced by new one since the weight increase is because of only one person add the old person weight+the average weight = 65+20 = 85.
B.E(Bekar Engg) said:
1 decade ago
Let average of 8 person weight = x;
x/8 = 2.5;
x = 8*2.5.
x = 20;
New person is add with weight = 65.
65+20 = 85.
Ans = 85;
x/8 = 2.5;
x = 8*2.5.
x = 20;
New person is add with weight = 65.
65+20 = 85.
Ans = 85;
Hemanth said:
1 decade ago
Weight of newly came person is = Weight of replaced person + (no of persons*increased in weight).
=>65+ (8*2.5).
=>65+20.
=>85.
=>65+ (8*2.5).
=>65+20.
=>85.
Vineela reddy said:
1 decade ago
@Manoj kumar is it useful for all?
Please give the clear information I'm ok but little confused.
Please give the clear information I'm ok but little confused.
Mukesh said:
1 decade ago
Old School method.
Let Z+65 be weight of 8 person and their average be A.
So, (z+65)/8 = A .......(i).
Now with the replacing the person with 65 KG weight with new person, average becomes A+2.5, let the weight of new person be x KG.
So, (Z+x/8) = A+2.5 .......(ii).
Subtraction (i) from (ii).
(x+65)/8 = 2.5.
Therefor, x = 85.
Let Z+65 be weight of 8 person and their average be A.
So, (z+65)/8 = A .......(i).
Now with the replacing the person with 65 KG weight with new person, average becomes A+2.5, let the weight of new person be x KG.
So, (Z+x/8) = A+2.5 .......(ii).
Subtraction (i) from (ii).
(x+65)/8 = 2.5.
Therefor, x = 85.
Jay said:
1 decade ago
In this case problems you people just recall this formula:
N - R = (+ or -)nx.
N - new items added.
R - removed items.
n - average of the sum.
x - decrease or increase.
Put + when increase.
- for decrease.
Now see:
N - 65 = + 8(2.5).
N = 85.
N - R = (+ or -)nx.
N - new items added.
R - removed items.
n - average of the sum.
x - decrease or increase.
Put + when increase.
- for decrease.
Now see:
N - 65 = + 8(2.5).
N = 85.
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