Question

The length, breadth and height of a room are 10 m,12 m and 9 m respectively.Find the cost of whitewashing its four walls at the rate of Rs. 8 per sq. meter.
2

Answer 1

$\fbox{\LARGE{ \underline{\underline{ \pink{ \bf{Given\: :}}}}}}$

Length = 10m, breadth = 12m and height = 9m

Rate of white washing Rs.8 per $m^2$

$\fbox{\LARGE{ \underline{\underline{ \pink{ \bf{Required \: answer:}}}}}}$

The cost of white washing the walls.

$\fbox{\LARGE{ \underline{\underline{ \pink{ \bf{Solution:}}}}}}$

We have,

l = 10m, b = 12m and h = 9m

${\LARGE{ { \pink{ \bf{Using \:the \:formula\:}}}}}}$

Area of four walls = 2(l +b)h = 2(10 + 12) × 9 = 2 × 22 × 9 = 396$m^2$

Now, cost of whitewashing 1$m^2$ = Rs.8

∴ cost of white washing 396$m^2$ = 396 × 8 = Rs. 3,168

${\LARGE{ { \pink{ \bf{Hence,\:the\:cost\:of \:white\:washing\:4\:walls\:=\\:Rs.3,168}}}}}}$

Answer 2

Answer:

Question

The length, breadth and height of a room are 10 m,12 m and 9 m respectively.Find the cost of whitewashing its four walls at the rate of Rs. 8 per sq. meter².

Given

• length= 10m
• breath= 12m
• height= 9m
• rate of white whitewashing= Rs. 8 per sq. meter².

Solution

$\boxed{ \sf{ \to \: area \: of \: four \: walls = 2h × ( l +b)}}$

where

• h denotes height
• l denotes lenght
• b denotes breath

Substitute the values in the above formula :

↝area of 4 walls = 2 × 9( 10+12)

↝area of 4 walls = 18 × 22

↝area of 4 walls = 396 m²

$\boxed{ \sf{ \to area \: of \: celing = ( l \times b)}}$

substitute the values

↝Area of celing = 10 × 12

↝ Area of celing = 120 m²

total area for white washing = area of 4 walls +area of celing

↝ total area for white washing = 396 + 120

↝ total area of white washing = 516 m²

➝Rate of white washing = Rs 8 per m²

➝Rate of white washing = 8× 516

➝ Rate of white washing = Rs 4128

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