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:
84 comments Page 5 of 9.
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.
Then, sum = 8x.
Now after replacement:
8x - 65 + y = 8 (x + 2.5),
8x - 65 + y = 8x + 20.
y = 65 + 20.
y = 85.
S S KUMAR said:
9 years ago
@NANDINI.
We are adding 20 to 65 because the average weight of 8 persons is being increased to 2.5 kg, by the new person who has been replaced by the existing one.
This directly implies that the new person who added into these will weigh more than the replaced one.
Hope you understand this.
We are adding 20 to 65 because the average weight of 8 persons is being increased to 2.5 kg, by the new person who has been replaced by the existing one.
This directly implies that the new person who added into these will weigh more than the replaced one.
Hope you understand this.
Sagar said:
9 years ago
Is there any shortcut method to solve this problem? Please help me.
Anil Kumar Basam said:
9 years ago
Total 9 person's average weight = 65 -> So, 65*9 = 585.
Every person comes in the place increases 2.5 -> So, 65 - 2.5 = 62.5.
8 persons average weight = 62.5.
Sum of the elements = average*total numberof elements.
=> 62.5*8 =500.
Sum of 9 persons - sum of 8 persons = 585 - 500= 85.
New person weight = 85kg.
Every person comes in the place increases 2.5 -> So, 65 - 2.5 = 62.5.
8 persons average weight = 62.5.
Sum of the elements = average*total numberof elements.
=> 62.5*8 =500.
Sum of 9 persons - sum of 8 persons = 585 - 500= 85.
New person weight = 85kg.
Naveen said:
9 years ago
The average of marks obtained in 120 students was 35. If the average of passed candidates was 39 and that of failed candidates is 15, the no of candidates who passed the examination is?
Nandini said:
10 years ago
Hai friends.
Can any one explain me why we add 20+65? Why not 20-65?
Can any one explain me why we add 20+65? Why not 20-65?
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).
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