Aptitude - Average - Discussion

10. 

In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother doest not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all are them are correct in their estimation, what is the average of different probable weights of Arun?

[A]. 67 kg.
[B]. 68 kg.
[C]. 69 kg.
[D]. Data inadequate
[E]. None of these

Answer: Option A

Explanation:

Let Arun's weight by X kg.

According to Arun, 65 < X < 72

According to Arun's brother, 60 < X < 70.

According to Arun's mother, X <= 68

The values satisfying all the above conditions are 66, 67 and 68.

Required average = 66 + 67 + 68 = 201 = 67 kg.
3 3


Pavan said: (Aug 31, 2010)  
How did take 66, 67 and 68 ?

Vinod said: (Nov 29, 2010)  
As arun said, his weight is greater than 65 kg, and mother said, his weight cannot be greater than 68 kg.
then value will be 65<=68
It means value is 66,67,68.
then Required average = 66 + 67 + 68 = 201 = 67 kg.

Sakshi said: (Feb 28, 2011)  
Can anyone explain it in another way? Please.

Jasmine said: (May 17, 2011)  
@Sakshi

As arun 65 to 72 so lets take 65,66,67,68,69,70,71 then as arun's brother 60 to 70 so delete 70,71 from the list then according to arun's mom surly less than or equal to 68 so delete 69 and 70 from list so finally lets take 66,67,68 k.. simple...

Mini said: (Jul 10, 2011)  
@JASMINE.

You explained it very well.

Ashwini said: (Aug 4, 2011)  
@jasmine

Explained very well. Thank you. :-)

Sathiya said: (Sep 10, 2011)  
Can i explain like this

According to arun 65to72

then he's brother 60to70

He's mother 68

Then 65+72+60+70+68=335
335/5=67

The answer is 67 .
This method right or wrong explain anyone.

James Silberschatz said: (Oct 6, 2011)  
71+69+68/3=6.33

Suman said: (Oct 7, 2011)  
I don't understand anyone explain again.

Gopal said: (Nov 8, 2011)  
Arun-65+72/2=68.50
brother-60+70/2=65.00
mom- 68.00
total
=201.50/3= 67

Raghavendar said: (Feb 18, 2012)  
His mother's view is that his weight cannot be greater than 68 kg
but she cant said that >=68
so the solution is 66+67/2=133/2=66.5
answer is none of these..

Uma said: (Feb 23, 2012)  
I got ans like tis way..., may i dont know whether is it correct r nt
view of arun avg=(65+72)/2=68.5
view of his brothers avg=(60+70)/2=65
view of his mother taken as=68
Therefore the avg of above three as=(68.5+65+68)/3=67

Venkat said: (May 12, 2013)  
Arun says that his age is > 65 but < 72
Therefore his age in between 66 to 71.

View of his brother, Arun's age is >60 but < 70,
Therefore Arun's age in between 61 to 69.

View of his mother, Arun's age is Cannot be > 68,
That means Arun's age under 68 years only.


The above three members opinions Arun's age in in between 66 years to 68 years,

Then (66+67+68)/3.

Mahesh said: (Oct 4, 2013)  
65 - 72 -(1) : 68.5.

60 - 70 -(2) : 65.0.

68 -(3) : 68.0.
-------
201.5/3 = 67.

Lalit Kumar said: (Jan 3, 2014)  
Logic Concept:

Let Arun age is X.
In Arun's opinion: 65 > X < 72.
Possibilities: 66, 67, 68, 69, 70, 71.

In Brother's opinion: 60 > X < 70.
Possibilities: 61, 62, 63, 64, 65, 66, 67, 68, 69

In Mother's opinion: X <= 68.
Possibilities: 1, 2, 3......61, 62, 63, 64, 65, 66, 67, 68.

Now check what similar terms are matching in every 3-possibilities i.e 66, 67, 68.

To find Average age = (66+67+68)/3.

Note: 3 = Three possible values. It is not Arun+Brother+Mother at all.

Niraj said: (Apr 23, 2014)  
((65+72)+(60+70)+(68))/5 = 67.

Anwi said: (Jun 28, 2014)  
The average age of man and son is 40 years. The ratio of their ages is 11:5 respectively. What is the son's age ? Solve it.

Vinodh said: (Jul 16, 2014)  
@Anwi.

40/0.5 = 80 man = 80*11/16 = 55 and son's age = 80-55 = 25.

Whether the answer & method is right or wrong explain anyone?

Rituraj said: (Aug 3, 2014)  
Why aren't we assuming fractional values?

Myvizhimalar said: (Aug 25, 2014)  
In The Given Problem, they said that Arun assume that his age will be more than 65 and less than 70,
A--> 65<A<75.

His brother's, 60< A < 70.
His Mom's opinion is, A<=68.

So the common numbers by the above three conditions are 66, 67, 68
by(66+67+68)/3 = 201/3 = 67kg.

Abhishek said: (Sep 5, 2014)  
Actually they want probable Weight or we can say avg weight.

So the simplest way to solve this Question is like that.

All the weights are Greater than or less than each other so easily we can find out their avg like.

65+72+60+70+68=335/5.

Answer will be 67 kgs.

Harsha said: (Jan 31, 2015)  
From the question itself. We are going to know that the age is in between 65-68.

So 66, 67, 68.

Why 66.....because. It should be greater than 65 as @Arun said Why 67....because as per his brother opinion <60 & >70.

As per his mother his age is definitely 68. So eliminate 69, 70 so according to his brother. His age is 67....why 68..... his mother gave a statement that he is 68 years old.

Venu said: (Feb 11, 2015)  
Guys,

If the given numbers are in A.P and no. of. numbers is odd number, then average of the whole is just the middle term or the average of first and last numbers.

E.g:- Average of 66, 67 and 68 is 67 only.

No need to do 66+67+68/3.

Use above formula and quickly answer it.

Hemanth Kothuru said: (Oct 23, 2015)  
Weight can also be non integer so given answer is definitely wrong. So the possible way considering all of them are correct is 65<w<68.

So minimum weight is 65+x (x is very very small) and maximum weight is 68. So therefore average weight is 66.5.

Muneer said: (Jan 6, 2016)  
Can anyone explain in a simple way?

Vasan said: (Apr 12, 2016)  
@Venu, explained very well.

Ashwini Madne said: (May 24, 2016)  
According to Arun, 65 < X < 72.
[(65 + 72/2) = 68.5 ie 69].

According to Arun's brother, 60 < X < 70.
[(60 + 70/2) = 65].

According to Arun's mother, X <= 68.

Required Average = (69 + 65 + 68)/3.
= 202/3.
= 67.33 i.e 67kg ==> answer.

Rajeshwari said: (Aug 1, 2016)  
Thank you @Sathiya.

Thiruppathy said: (Aug 14, 2016)  
@Anwi,

The answer is 133. Am I right?

Prateek Bhaiya said: (Sep 4, 2016)  
Acccording to me,

Given condition : x > 65 & amp; x < 72(according to Arun opinion).
x > 60 & x < 70(according to Arun's brother).
x < = 68(according to Arun's mother).
So, average age = 65 + 72 + 60 + 70 + 68/5.
335/7 = 67.

Ans is 67.

Navneet Gupta said: (Sep 22, 2016)  
As per the condition, only three ages i.e 66, 67, 68 comes in range. And the average will be 67.

Mandeep said: (Dec 4, 2016)  
Thanks Prateek for clear solution.

Rahul said: (Jan 17, 2017)  
We can do like that

56 + 72 + 60 + 70 + 68 = 335.
335 ÷ 5 = 67 answer.

Ashish said: (Jan 20, 2017)  
There is not mentioned that >= means 66+67/2 = 66.5.

So, answer is none of these.

Harika said: (Apr 18, 2017)  
Nice explanation thank you @Jasmine.

Abhay said: (May 18, 2017)  
67 is not the correct answer.

The correct answer is 66.5.
(65+68)/2=66.5

So the correct answer is option E.

Nitishpandey said: (Jul 27, 2017)  
@Anwi.

Son and father average age =11x+5x in linear sequence 11x is father and 5x is son,
11x+5x=40 so,
(11x+5x)=40 * 2 because here only possibility of two person father and son,
16x=80,
x=5.

Then son age = 5 * 5
So ans 25,

Hope you understand.

Abdul Waheed said: (Feb 2, 2018)  
You are right, Thanks @Gopal.

Jaya Priya said: (May 11, 2018)  
Well explained, thank you @Jasmine.

Rohit said: (May 17, 2018)  
There was not given any condition to consider weights as integer values.

Why take 66, 67 & 68 only?

Well, If he's greater than 65, And what he thinks is correct. He can weight, for instance, 65.1 or maybe 65.2.

Someone help me out here.

Kiran Labade said: (Jun 16, 2018)  
Let's Arun weight be x.

Limit in between:

1st Arun : 65 < x < 72,
2nd Brother: 60 < x < 70,
3rd Mother : 68 < = x.

Therefore, for possible values average of each approximate values
65 + 72 = 137 /2 = 68.5 (Lower Limit + Upper limit)/2,
60 + 70 = 130 / 2 = 65,
0 + 68 = 68.

Total average ages are 68.5+65+68 = 201.5.
for three limit values hence divide by three = 201.5/3 = 67.16 (float value).

we get a float value 67.16 it is complete a boundary of 67 but not a complete boundary of 68 or 69.

Hence, the approximate value of Answer is 67 kg. [A]

Ankit said: (Jul 31, 2018)  
If it is greater than and less than why don't we take x+65 and x-70?

Yazdani said: (Aug 12, 2018)  
Arun's opinion between 65 to 72 kg.

So avg of Arun's opinion= 66+67+68+69+70+71÷ 6 = 68.5 --> 1
Aruns bro opinion btwetween 60 to 70kg.

Avg =61+62+63+64+65+66+69 ÷ 7 = 65 --> 2.

Arun's opinion is 68 --> 3.
Take the avg of eq 1,2,3.
We get 67.

Utkarsh Patil said: (Sep 8, 2018)  
Why did anyone not take probable weights from 65.1 to 67.9?

Kshitij Gupta said: (Sep 18, 2018)  
The answer of the question is wrong as it is based upon the assumption that the weight has integral values only which is not stated anywhere in the question.

The correct solution would be as follows:
Arun's opinion: 65-72
Brother's opinion: 60-70
mother's opinion: <68.

Therefore to find the average of the all probable weights of Arun we take the average of the lower and the upper limits:

Average of lower limits: (65+60)/2 = 62.5.
Average of upper limits: (72+70+68)/3 = 70.
Therefore the average of the possible weights of Arun would then be the middle most value of this range hence: Average of all probable weights = (62.5 + 70)/2 = 66.25 (ANS).

Shubham J said: (Jan 31, 2019)  
Arun's statement : (65+72)/2 = 68,
Arun's brother statement : (60+70)/2 = 65,
his mother statement : 68.
Now (68+65+68)/3 = 67.

Pankaj said: (Apr 10, 2019)  
Avg of least and most value is 60 + 72/2 = 66.
Her mother said not greater than 68.
So, Avg of 66 + 67 + 68/3 = 67.

Minu said: (Apr 12, 2019)  
You can also average all 5 numbers:
60+72+68+65+70 = 335,
335/5 = 67kgs.

Madhu said: (Jul 4, 2019)  
@All.

Once Ajay went to the office of ROCK LINE COURIER with 4 different envelopes. The clerk in the office measured the weights in all possible pairs. The weights obtained are 59gm, 61gm, 62gm, 63gm, 64gm and 66gm. What is the weight of the heaviest envelope?

Can anyone solve it?

Ashu said: (Aug 18, 2019)  
@Jasmine.

You explained it very well.

Supon Sam said: (Aug 20, 2019)  
Thanks for explaining @Vinod and @Jasmine.

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