Aptitude - Area - Discussion

Each of these questions is followed by three statements. You have to study the question and all the three statements given to decide whether any information provided in the statement(s) is redundant and can be dispensed with while answering the given question.


What is the cost painting the two adjacent walls of a hall at Rs. 5 per m2 which has no windows or doors?


The area of the hall is 24 sq. m.


The breadth, length and height of the hall are in the ratio of 4 : 6 : 5 respectively.


Area of one wall is 30 sq. m.

[A]. I only
[B]. II only
[C]. III only
[D]. Either I or III
[E]. All I, II and III are required.

Answer: Option C


From II, let l = 4x, b = 6x and h = 5x.

Then, area of the hall = (24x2) m2.

From I. Area of the hall = 24 m2.

From II and I, we get 24x2 = 24         x = 1.

l = 4 m, b = 6 and h = 5 m.

Thus, area of two adjacent walls = [(l x h) + (b x h)] m2 can be found out and so the cost of painting two adjacent walls may be found out.

Thus, III is redundant.

Correct answer is (C).

Habib said: (Feb 11, 2011)  
Can anyone explain?

Henderson said: (Jun 14, 2011)  
Why (C) ?

Ajay said: (Sep 29, 2011)  
Please explain why we take (C) OPTION.

Balaji said: (Dec 17, 2011)  
Can anyone explain this?

Rachitj571 said: (Mar 4, 2012)  
It should be D. X=1 can also be obtained using II and III statements. In that case I will become redundant.

Arthi said: (Mar 29, 2013)  
Given area of one wall = 30 sq.m.

Therefore area of two adjacent walls = 60 sq.m.

Cost of painting two walls = 60*5 = Rs.300.

Thus option C is correct.

Vivek Bharti said: (Jul 12, 2013)  
Given area of one wall = 30 sq.m.

b:l:h are in ratio 4:6:5.

Therefore l=6 and h=5 also b will be 4.

Therefore area of two adjacent walls = 50 sq.m.(l*h+b*h).

Cost of painting two walls = 50*5 = Rs.250.

Vivek Bharti said: (Jul 12, 2013)  
It should be D because we can calculate the cost by either using I and II or by II and III. So, either I or III will be redundant.

Vibhor said: (Aug 30, 2013)  
The option is incorrect it should be either 1 or 2.

Amy Saw said: (Aug 2, 2014)  
The option is incorrect.

Option 3 is redundant.

So, Right answer is Both 1 and 2 option.

Monster said: (Oct 3, 2014)  
In the explanation it is said that we need I and II. Then how comes C(III only) as the right option.

Ajit said: (Nov 20, 2014)  
Correct answer is E. As for finding area of adjacent walls we need II and then either I or III but as its only satisfying by option E so its correct.

Vampire said: (Nov 22, 2014)  
Area of the hall is l*b and we don't need height the area is given and the ratio is also given with this we can easily find the answer and 3 is unnecessary for this problem. Hence C is the answer.

Farheen said: (Jun 21, 2015)  
How come area of hall should be l*b?

Should it not include 4 walls, 1 floor and 1 ceiling?

Chhandak said: (Aug 26, 2015)  
Area of the hall which is going to be painted will include 4 walls and the ceiling and the floor is never painted.

So I don't think its 24x^2 simply. There is something wrong.

Rusty said: (Oct 2, 2015)  
Without I & II we can't calculate.

Ankush said: (Jul 29, 2016)  
According to me, the correct answer should be E.

Asha said: (Jul 30, 2016)  
Right answer is E. As Answer C gives Area of one wall only.

Akhil said: (Aug 7, 2016)  
The correct answer is D.

Mahich said: (Aug 24, 2016)  
How the area of the hall is equal to 24X^2?

Because 24X^2 is Floor's area. Not hall's area.

Kuldeep said: (Aug 25, 2016)  
The Correct answer is C as the area of one wall is not specified. We can take any of them & two different solutions will be obtained which is not clear for determining the cost of painting.

Appa Rao said: (Nov 13, 2016)  
According to the question option E will be the answer.

Shradha said: (Jul 21, 2017)  
The answer is correct as the question asks us to select the redundant option. We can estimate the cost from I and II, therefore III is not required.

So, the correct answer is in fact option (c).

Manus said: (Jun 27, 2018)  
Actually, what is the correct answer? Please explain.

Pavan said: (Aug 2, 2018)  
The right answer would be I and II are sufficient.

Because with I and II we will get to know the measurements of all the sides.

And no need of III.

Shweta Kashyap said: (Aug 24, 2019)  
Here, the area of one wall is given which is not the area of the adjacent wall because one wall would have length and the adjacent would have the breadth and it is nowhere given that length and breadth are equal.

Shivam said: (Apr 3, 2020)  
According to me, it should be E.

Only cost of painting is given in question.

ll is needed to know the ratio of all dimensions and ratio of all areas of the hall.
l is needed to know the actual value of all the areas.
then only we can find the total cost without lll also but how can we find the areas of both the walls with just lll given.

Mahesh said: (Nov 3, 2021)  
Yes, you are right @Vivek Bharti.

I think D should be the right answer.

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