Aptitude - Average - Discussion

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).

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]

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.

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.

In this question ,
Arun => 65 < x < 72.
Arun's brother => 60 < x < 70.
Arun's mother => x <= 68.

So,
Let me ask you guys,

The weight should be greater than 65 and less than or equal to 68
Since weight can be 65.00000....001 to 68
How can we predict the average weight as 67?
Weight can take decimal values also right?
Data Inadequate isn't it?

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.

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.

@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?

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.

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.