Aptitude - Volume and Surface Area - Discussion

Discussion Forum : Volume and Surface Area - General Questions (Q.No. 3)
3.
A hall is 15 m long and 12 m broad. If the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls, the volume of the hall is:
720
900
1200
1800
Answer: Option
Explanation:

2(15 + 12) x h = 2(15 x 12)

h = 180 m = 20 m.
27 3

Volume = 15 x 12 x 20 m3 = 1200 m3.
3

Video Explanation: https://youtu.be/V8EQ1YIaH74

Discussion:
75 comments Page 1 of 8.

Debasish Sethy said:   5 years ago
According to the question,

Sum of areas of floor and the ceilings= 4 walls area sum
Floor area = ceiling area.
Floor area= 12 * 15 = 180.
Therefore 360 = 4 areas of walls.
Floor-length = wall length.
So height of the wall = (360/4)/15= 90/15 = 6m.
the volume of the hall is one type of cuboid.
Therefore volume of cuboid = length * breadth * height.
Volume = 15 * 12 * 6 = 1080 meter cube.
(15)

Subash chander said:   6 years ago
Roof + ceiling area = 4 side walls.

W.k.t area of rectangle l x b.

(12 x 15) + (12 x 15)= 12h + 15h + 12h + 15h.
2(12 x 15) = 2(12h + 15h).
2(12 x 15) = 2h(12+15).
2(12 x 15)
----------------- = h
2 x 27

Volume = LBH.
L=15 b=12 and h is 54.
Then, Volume= 1200.
(8)

Surajbhan Singh said:   6 years ago
2*(l*h)+ 2*(b*h)= 2*(l*b).

4 walls area = floor area + ceiling area.
(7)

Bharath bhargav said:   3 years ago
The area of the cuboid 2(l+b)*h.
(5)

Afework said:   1 year ago
No the answer is 600
How can we get hight is 27
Is 3.33
(3)

YASH said:   6 years ago
The solution is wrong as it is said it is equal to the area of the 4 walls so, 4 should be multiplied.
(2)

Manoj said:   8 years ago
Floor Area = 15 x 12 = 180 m.
Ceiling Area = 15 x 12 = 180 m.

Sum of Floor & Ceiling Area = 180 + 180 m = 360 m
- now,in the question "f the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls." it means ,
360+360 = 720.

Please, help me to get it.
(2)

Geethu said:   1 decade ago
2(15*12)=2(lh+bh)
=2h(l+b)
15*12 = h(15+12)
h=(15*12)/(15+12)=180/27
(1)

Mapuia sailo said:   5 years ago
Why we using the cuboid formula? Please explain.
(1)

Jordan said:   1 decade ago
Here given that

Area of four walls = (area of the base )+(area of ceiling)

Area of base is (l*b)
Area of ceiling is (l*b)
so (area of the base )+(area of ceiling)=2(l*b)

As per Surface area of a cuboid we have 2(l+b)*h
Area of four walls=2(l+b)*h
(1)


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