Question

a hall is 36m long and 24m broad. Allowing 40 square meters for doors and windows, the cost papering the walls at Rs. 8.40 per square meter is Rs. 4704.find the height of the hall. ​

Answer 1

Step-by-step explanation:

Cost= Rate×SA

SA=4704÷0.8

= 5880

Now,.

CSAof cuboid+ Area of Terrace=5880

2h(36+24)+36×24=5880

2h×60+864=5880

h×60+864=5880/2

h=2940/144

h=20.14(approx)

Answer 2

Answer:

5 metres

Step-by-step explanation:

• The cost of papering the walls = Rs 4704

• Rate of Papering the walls = Rs 8.40 per m²

The Prepared Area = ( Total cost / Rate /m² )

= ( 5704 / 8.40 ) m² = 560 m²

: $\implies$ Areas of door and windows = 40 m²

Total Area of 4 walls = ( 560 + 40 ) m² = 600 m²

: $\implies$ length of the hall = 36 m,

: $\implies$ breath of the hall = 24 m

let the hight of the hall be h metres .

: $\implies$ Then, Area of 4 Walls = { 2 ( Length + breadth ) x Height } Sq unit

$\implies$ { 2 ( 36 + 24 ) x h } m² = (120 h ) m²

: $\implies$ ∴ 120 h = 600 <=> h = 600 / 120 = 5

Hence, the hight of the hall is 5 metres

★ Additional information:

• Do not get confused with the length and breadth of the hall to be the length and breadth of the wall. You need to keep in mind that the hall will have two walls of different dimensions and the two opposite walls of the same dimensions.

• So, the length of the hall will be the length of one wall and the breadth of the hall will be the length of another wall. Cost of construction will be the product of the total area of construction and the cost of construction per unit area.

• Every wall will be rectangular in shape. The given information about the hall will be the lengths of adjacent walls. The height of all the walls will be the same. Calculate the total area of the walls in terms of height, h. of the wall. Subtract the area left for doors and windows. And the compare it with the cost of constructing those walls to find the value of h