Question

length breadth and hight of a room are 15m,12m and 8m, respectively find the cost of white washing the room at the rate of rs8 per m if it has a door measuring 4m×1.5m and to windows each measuring 3m×2.5m​

Answer 1

Answer:

51.375

Step-by-step explanation:

surface area of room= 2(12×8+8×15)

2(216)

432m2

also, cost of white washing= 411/8

51.375

Answer 2

$\huge\fcolorbox{red}{cyan}{₹ 952}$

Step-by-step explanation:

First Lets Calculate The Total Surface Area of Room :-

• Length(l) = 15 m
• Breadth(b) = 12 m
• Height(h) = 8 m
• Total Surface Area(T.S.A.) = ?

$\bf\color{purple}{T.S.A. = [2(l+b)(b+h)(h+l)]} \\ => \bf{Lets\:Put\:The\:Values} \\ => 2[(15+12)(12+8)(8+15)] \\ => 2(27 + 20 + 23) \\ => 2 \times 70 \\ =>\boxed{140}$

Thus The T.S.A. Of The Room Is 140 m²

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Area of Door :-

• Length = 4 m
• Breadth = 1.5 m
• Area = ?

$\bf\color{orange}{Area\:Of\:Door = l \times b} \\ => 4 \times 1.5 \\ => \boxed{6 \:m²}$

Thus The Area of Door is 6 m²

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Area of 2 windows :-

• Length = 3 m
• Breadth = 2.5 m
• Area = ?

$\color{blue}{2(l \times b)} \\ => \bf{Lets\:Put\:The\:Values} \\ => 2 (3\times 2.5) \\ => 2 \times 7.5 \\ => \boxed{15}$

Thus The area Of Two windows is 15 m²

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Area of Room Without Doors and Windows :-

• Area of Room = 140 m²
• Area Of Door = 6 m²
• Area Of Windows = 15 m²

$Area\:Of\:Only\:Room = (Area\:Of\:Whole\:Room)-(Area\: of \:Door+Area\: of\: windows) \\ => \bf{Lets\:Put\:The\:Values} \\ => 140 - (6 + 15) \\ => 140 - 21 \\ => \boxed{119}$

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Finally The Cost Of White-Washing The Room :-

$Cost\:Of\:Washing\:The\: 1\:m²= ₹ 8 \\ => Cost\:Of\:Washing \:119 m² = ₹ 8 \times 119 \\ =>\boxed{952}$

Thus The Cost is ₹ 952

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