Advertisements
Advertisements
Question
The length of a hall is 18 m and the width 12 m. The sum of the areas of the floor and the flat roof is equal to the sum of the areas of the four walls. Find the height of the wall.
Advertisements
Solution
\[\text { Length of the hall = 18 m }\]
\[ \text { Its width = 12 m } \]
\[\text { Suppose that the height of the wall is h m } . \]
\[\text { Also, sum of the areas of the floor and the flat roof = sum of the areas of the four walls } \]
\[ \Rightarrow 2 \times\text { (length }\times \text { breadth)
}= 2 \times \ \text { (length + breadth) }\times \text { height }\]
\[ \Rightarrow 2 \times (18 \times 12) = 2 \times (18 + 12) \times h\]
\[ \Rightarrow 432 = 60 \times h\]
\[ \Rightarrow h = \frac{432}{60} = 7 . 2 m\]
\[ \therefore \text { The height of wall is 7 . 2 m . }\]
RELATED QUESTIONS
Daniel is painting the walls and ceiling of a cuboidal hall with length, breadth, and height of 15 m, 10 m, and 7 m, respectively. From each can of paint, 100 m2 of area is painted. How many cans of paint will she need to paint the room?
The dimensions of a rectangular box are in the ratio of 2 : 3 : 4 and the difference between the cost ofcovering it with sheet of paper at the rates of Rs. 8 and Rs. 9.50 per m2 is Rs.1248. Find the dimensions of the box.
A cuboidal block of silver is 9 cm long, 4 cm broad and 3.5 cm in height. From it, beads of volume 1.5 cm3 each are to be made. Find the number of beads that can be made from the block.
A tea-packet measures 10 cm × 6 cm × 4 cm. How many such tea-packets can be placed in a cardboard box of dimensions 50 cm × 30 cm × 0.2 m?
Find the volume in cubic metre (cu. m) of the cuboid whose dimensions is length = 10 m, breadth = 25 dm, height = 50 cm.
The dimensions of an oil tin are 26 cm × 26 cm × 45 cm. Find the area of the tin sheet required for making 20 such tins. If 1 square metre of the tin sheet costs Rs 10, find the cost of tin sheet used for these 20 tins.
The length, breadth and height of a rectangular solid are in the ratio 5 : 4 : 2. If the total surface area is 1216 cm2, find the length, the breadth and the height of the solid.
If the edge of a cube is 8 cm long, find its total surface area.
The areas of any two faces of a cuboid are equal.
External dimensions of a closed wooden box are in the ratio 5:4:3. If the cost of painting its outer surface at the rate of Rs 5 per dm2 is Rs 11,750, find the dimensions of the box.
