Question

a conference hall is 14m long 8m wide and 4m high there are 4 windows and one door in it the door measures 1m by 2m and each window measures 1m by 1.5m. how many litres are needed. to paint all the walls of the hall if one litre. is enough. for covering 18m2

Answer 1

answer is 28/3
as surface area of walls is 2h(l+b) or 2*4(14+8) or 8*22=176
area of windows = 4(1*1.5) or 6
area of door =1*2 or 2
6+2=8
(176-8)18=168/18 or 28/3 or 9 and 1/3 litres

Answer 2

Answer:

21.78 liters

Step-by-step explanation:

Length of hall = 14 m

Breadth of hall = 8 m

Width of hall = 4 m

Total surface area of hall =$2(lb+bh+hl)$

                                          =$2(14 \times 8 + 8 \times 4 + 4 \times 14)$

                                          =$400 m^2$

Length of door = 1 m

Breadth of door = 2 m

Area of door = $Length \times Breadth = 1 \times 2 = 2 m^2$

Length of window = 1 m

Breadth of window = 1.5 m

Area of 1 window = $Length \times Breadth = 1 \times 1.5 = 1.5 m^2$

Area of 4 windows = 1.5 *4 = 6 sq.m.

Area need to be painted = Area of Hall - (Area of 1 door+Area of 4 windows)

Area need to be painted = 400 - (2+6) = 392 sq.m.

Liters of paint for covering 18 sq.m. = 1 liter

Liters of paint for covering 392 sq.m. = $\frac{1}{18} \times 392=21.78 liters$

Hence 21.78 liters are needed. to paint all the walls of the hall if one liter. is enough. for covering 18 sq.m.