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?
76 kg
76.5 kg
85 kg
Data inadequate
None of these
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:
84 comments Page 8 of 9.

Honey said:   10 years ago
But one person is excluded from 8 and a new person comes?

Victor said:   10 years ago
Can I have some more tricks?

Mahnoor said:   10 years ago
I'm totally confused. Why method change again an again?

Saravanan said:   10 years ago
Replaced value+(Increase in average*Total number of observation).

Priyanka VERMA said:   9 years ago
Let average = x.
Then, sum = 8x.

Now after replacement:

8x - 65 + y = 8 (x + 2.5),
8x - 65 + y = 8x + 20.
y = 65 + 20.
y = 85.

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.

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;

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.


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