Question

The length, breadth and height of a room are 5 m, 4 m and 3 m, respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of ₹17.50 per m2.
Solution:​

Answer 1

#verified answer

Length= 5m

Breadth= 4m

Height= 3m

=> (C.S.A of the wall + area of upper part)

=> l(h+b) + l*b

=> 5(4+3) + 5*4

=> 35 + 20

=> 55 sq.m

Rate per sq. m = ₹17.50

therefore,

therefore,the cost of white washing the walls of the room=

=> 55 sq.m* ₹17.50

=> ₹962.50

Therefore, your answer is ₹962.50.

Answer 2

Question ::-

The length, breadth and height of a room are 5 m, 4 m and 3 m, respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of ₹17.50 per ${m}^{2}$

Given ::-

• Length of room = 5m

• Breadth of room = 4m

• Height of room = 3m

• Cost of ceiling per ${m}^{2}$ = Rs. 17.50

To find ::-

• Cost of washing ?

Solution ::-

• Length of the room (l) = 5 m

• Breadth of the room (b) = 4 m

• Height of the room (h) = 3 m

_________

The room is like a cuboid whose four walls (lateral surface) and ceiling are to be white washed.

∴ Area for white washing

$= [Lateral \: surface \: area] + [Area \: of \: the \: ceiling]$

$= [2(l + b)h] + [l \times b]$

$= [2(5 + 4) \times 3] {m}^{2} +(5 \times 4) {m}^{2}$

$= 54 {m}^{2} + 20 {m}^{2}$

$= 74 {m}^{2}$

__________

Cost of white washing for 1 ${m}^{2}$ area = Rs. 7.50

∴ Cost of white washing for 74 ${m}^{2}$ area

= Rs. (7.50 x 74)

= Rs. 555

Thus, the required cost of white washing = Rs. 555