Question

Find the cost of painting the 4 walls of a
room having length 12m breadth 10m
and height 8m at the rate of 35 per m2.
Rs 12,320
Rs 12,340
Rs 12,354
Rs 12,960​

Answer 1

$\underline{ \underline{ \Large \pmb{\mathit{ {Given:}} }} }$

• Length of the room = 12 m

• Breadth of the room = 10 m

• Height of the room = 8 m

• Cost of painting 4 walls per m² = Rs. 35

$\underline{ \underline{ \Large \pmb{\mathit{ {To \: calculate:}} }} }$

• Total cost of painting the 4 walls of a room.

$\underline{ \underline{ \Large \pmb{\mathit{ {Calculation:}} }} }$

Here, we are given the length, breadth and the height of the room that is 12 m, 10 m & 8m. We have to find the total cost of painting the 4 walls of a room. In order to find it, we need to calculate the area of the four walls of the room. And then as the cost of painting 4 walls per m² is Rs. 35, so the total cost of painting the 4 walls of a room will be Rs. 35 times the area of the 4 walls of the room.

⠀⠀⠀⠀⠀_____________

$\longrightarrow \boxed{\sf { {Area}_{(4 \: Walls \: of \: Room)} = {L.S.A}_{(Room)} }}$

$\longrightarrow \sf { {Area}_{(4 \: Walls \: of \: Room)} = 2(l+b) \times h }$

$\longrightarrow \sf { {Area}_{(4 \: Walls \: of \: Room)} = 2(12+10) \times 8 \: {m}^{2} }$

$\longrightarrow \sf { {Area}_{(4 \: Walls \: of \: Room)} = 2(22) \times 8 \: {m}^{2} }$

$\longrightarrow \sf { {Area}_{(4 \: Walls \: of \: Room)} = 44 \times 8 \: {m}^{2} }$

$\longrightarrow \sf { {Area}_{(4 \: Walls \: of \: Room)} = 352\: {m}^{2} }$. . . . ★

Now, calculating the total cost of painting the 4 walls of a room.

$\longrightarrow \boxed{\sf { {Total \: Cost}_{( \: Painting4 \: Walls )} = {Cost}_{(1 \: {m}^{2} )} \times {Area}_{(Four \: Walls)} }}$

$\longrightarrow \sf { {Total \: Cost}_{( \: Painting4 \: Walls )} = Rs. \: ( 35 \times 352) }$

$\longrightarrow \boxed{ \pmb{\rm \red{ {Total \: Cost}_{( \: Painting4 \: Walls )} = Rs. \: 12320}}}$

Therefore, total cost of painting the 4 walls of a

room is Rs. 12320 and Option A is correct.