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Aptitude - Area - Discussion

Discussion Forum : Area - Data Sufficiency 3 (Q.No. 2)
Area
Directions to Solve

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.

2.

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

I. 

The area of the hall is 24 sq. m.

II. 

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

 III. 

Area of one wall is 30 sq. m.

I only
II only
III only
Either I or III
All I, II and III are required.
Answer: Option
Explanation:

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).

Discussion:
30 comments Page 1 of 3.
Rishabh Jain said:   3 years ago
The Given Answer is correct.

If we use statements II and III only.

Then area of one wall = 30 sq. m, which could imply either b*h or l*h.
Statement 2 => b = 4x, l = 6x, h = 5x.
i.e. 4x*5x = 30 => x = 1.224 OR 6x*5x = 30 => x = 1.

Both of these would give 2 different answers as the length, breadth or height need not be in the whole number.

While, if we use Statements I and II.
Statement 1 => l*b = 24.
Statement 2 => b = 4x, l = 6x, h = 5x.
6x*4x = 24; x = 1.
Then, the answer can be calculated

The only discrepancy in the question is the misleading information "Area of the Hall" assumed to be equal to the area of the base of the hall (L*B), when it could be the total area of the hall i.e. 2*(L*B + L*H + B*H).
Shivam said:   5 years ago
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.
Shweta kashyap said:   6 years ago
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.
Vivek Bharti said:   1 decade ago
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.
Shradha said:   8 years ago
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).
Vampire said:   1 decade ago
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.
Kuldeep said:   9 years ago
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.
Chhandak said:   1 decade ago
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.
Arthi said:   1 decade ago
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.
Pavan said:   7 years ago
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.
(3)
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