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.
Naveen Kumar K said:
7 years ago
Thanks for the answer. @Bhanu.
Abhi said:
3 years ago
@Tinku.
Thanks for your explanation.
Thanks for your explanation.
Iman said:
3 years ago
@Manoj Kumar.
Thanks for explaining. Your method is very helpful to solve the QA questions.
Thanks for explaining. Your method is very helpful to solve the QA questions.
Shiya said:
1 decade ago
@kumar
Hi kumar in the problem they are saying that it wil be effect 2.5 kg that means may be new person weight will be greater than other remaining 7 persons. In this situation they may be effect rite.
Hi kumar in the problem they are saying that it wil be effect 2.5 kg that means may be new person weight will be greater than other remaining 7 persons. In this situation they may be effect rite.
Swetha said:
1 decade ago
Why do you add 20 for calculating the weight of new person? how is that logic?
Rahul said:
1 decade ago
It is not given in question that average weight of each was 65 kg instead it was the weight of only that person who was replaced so they have assumed and done wrongly.
Amar Sahoo said:
1 decade ago
Let us take 'x' be the new person.
'x' replaces the person having 65 kg weight i.e. x-65.
Total weight increased = (8 x 2.5) kg = 20 kg.
So we can put it in an equation i.e.
x - 65 = 20.
x = 20 + 65.
x = 85 ANS.
'x' replaces the person having 65 kg weight i.e. x-65.
Total weight increased = (8 x 2.5) kg = 20 kg.
So we can put it in an equation i.e.
x - 65 = 20.
x = 20 + 65.
x = 85 ANS.
Sandeepkumar said:
1 decade ago
Let x be the average weight,
Total weight incremented is = x+ 2.5.
Then,
avg.
7x-65 = 8(x+2.5).
7x-65 = 8x+20.
Then x = 85.
Total weight incremented is = x+ 2.5.
Then,
avg.
7x-65 = 8(x+2.5).
7x-65 = 8x+20.
Then x = 85.
Karthik said:
1 decade ago
(w1+w2+w3+...+w8)/8 = x kg - eq1.
Let w2 be the person who has been replaced.
Let it be denoted by w2n.
So now,
(w1+w2n+w3+....+w8)/8 = x+2.5 - eq2.
Replacing x in eq2 with x from eq1 we get,
w2n-w2 = 20.
=> w2n = 85.
Let w2 be the person who has been replaced.
Let it be denoted by w2n.
So now,
(w1+w2n+w3+....+w8)/8 = x+2.5 - eq2.
Replacing x in eq2 with x from eq1 we get,
w2n-w2 = 20.
=> w2n = 85.
Rahul said:
1 decade ago
Avg = x.
Sum of 8 person's weight/8 = x.
Sum of 8 person's weight= 8x.
Sum of 8 person's weight = 8x+20.
8x+20-8x-20=0.
8x+20-8x = 20.
Therefore 20+65=85.
Sum of 8 person's weight/8 = x.
Sum of 8 person's weight= 8x.
Sum of 8 person's weight = 8x+20.
8x+20-8x-20=0.
8x+20-8x = 20.
Therefore 20+65=85.
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