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:
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 2 of 8.
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
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
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
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
Sravanthi said:
1 decade ago
@Sonu.
It's lh not lb in your explanation.
i.e Yes the surface area of cuboid is 2 (lb+bh+hl).
But surface area of 4 walls does not includes areas of floor+ceiling.
That's why total area of walls = 2(lb+bh+bl) - 2 (lb) = 2(hb+lh) = 2 (b+l)h.
It's lh not lb in your explanation.
i.e Yes the surface area of cuboid is 2 (lb+bh+hl).
But surface area of 4 walls does not includes areas of floor+ceiling.
That's why total area of walls = 2(lb+bh+bl) - 2 (lb) = 2(hb+lh) = 2 (b+l)h.
Shahid said:
1 decade ago
Here given that
Area of four walls = (area of the base )+(area of ceiling)
As per Surface area of a cuboid we have 2(l+b)*h
Area of base is (l*b)
So from these 2 formula e we get the equation explained in the answer section
Area of four walls = (area of the base )+(area of ceiling)
As per Surface area of a cuboid we have 2(l+b)*h
Area of base is (l*b)
So from these 2 formula e we get the equation explained in the answer section
Mukesh bajaj said:
1 decade ago
It's not the surface area of cuboid brother, here it codes,
We have,
Area of ceiling + ground = area of 4 walls.
( l*b)+(l*b) = (l*h)+(b*h)+(l*h)+(b*h).
L.H.S = 2(l*h)+2(b*h).
2(l*b) = 2h(l+b).
We have,
Area of ceiling + ground = area of 4 walls.
( l*b)+(l*b) = (l*h)+(b*h)+(l*h)+(b*h).
L.H.S = 2(l*h)+2(b*h).
2(l*b) = 2h(l+b).
Patty said:
9 years ago
Surface area of cuboid is 2 (lb + bh + hl).
But surface area of 4 walls doesnt includes areas of floor+ceiling. Thats why Total area of walls = 2 (lb + bh + bl) - 2 (lb) = 2 (hb + lh) = 2(b + l)h.
But surface area of 4 walls doesnt includes areas of floor+ceiling. Thats why Total area of walls = 2 (lb + bh + bl) - 2 (lb) = 2 (hb + lh) = 2(b + l)h.
Sonu said:
1 decade ago
Yes the surface area of cuboid is 2(lb+bh+hl)
But surface area of 4 walls doesnot includes areas of floor+ceiling. thats why Total area of walls = 2(lb+bh+bl) - 2 (lb) = 2(hb+lh) = 2(b+l)h
But surface area of 4 walls doesnot includes areas of floor+ceiling. thats why Total area of walls = 2(lb+bh+bl) - 2 (lb) = 2(hb+lh) = 2(b+l)h
Jay-r said:
7 years ago
Simple formula,
h= (l * b) / (l + b) thus,
h= (15 x 12) / (15 + 12)
h= (180) / (27),
h= 180/27.
Volume of rectangle = l * b * h
= 15 x 12 x 180/27,
= 1200 cubic meter.
h= (l * b) / (l + b) thus,
h= (15 x 12) / (15 + 12)
h= (180) / (27),
h= 180/27.
Volume of rectangle = l * b * h
= 15 x 12 x 180/27,
= 1200 cubic meter.
(1)
Anil said:
9 years ago
Imagine it as cuboid i.e it has different breadth and height also has length.
Given condition,
2(15h) = 2(15 * h) + 2(12 * h).
Solve this to get h.
lbh = v.
Given condition,
2(15h) = 2(15 * h) + 2(12 * h).
Solve this to get h.
lbh = v.
Arya said:
1 decade ago
Surface area of a cuboid we have 2(l+b)*h
and surface area of cuboid is 2 (lb + bh + lh) sq. units
whats the difference in this..
which apply where??
and surface area of cuboid is 2 (lb + bh + lh) sq. units
whats the difference in this..
which apply where??
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