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
7.50 per m.​

Answer 1

Answer:

₹750

Step-by-step explanation:

Area of 4 walls + ceiling = 5(5×4)

= 100m²

The cost of white washing per m² = ₹7.50

Therefore, total cost = 7.5 × 100 = ₹750 (ans)

Answer 2

$\begin{gathered}\frak{Given}\begin{cases}\sf{\: Length \ of \ room \ is \ \bf{5\: m}}\\\sf{\: Breadth \ of \ room \ is \ \bf{4 \: m}}\\\sf{\: Height \ of \ room\ is \ \bf{3 \ m}}\end{cases}\end{gathered}$

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$\star\:{\underline{\boxed{\sf{\pink{Area \ of \ ceiling = Length \times Breadth}}}}}⋆$

$\begin{gathered}:\implies\sf 5 \times 4 \\\\\\:\implies\boxed{\frak{\purple{ 20\: sq \ m}}} \end{gathered}$

$\begin{gathered}\\\end{gathered}$

$\star\:{\underline{\boxed{\sf{\pink{Area \ of \ four \ walls = 2h(Length+ Breadth)}}}}}⋆$

$\begin{gathered}:\implies\sf 2 \times 3 (5 + 4) \\\\\\:\implies\sf 6 \times 9\\\\\\:\implies\boxed{\frak{\purple{54 \ sq \ m}}}\end{gathered}$

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Therefore,

⠀⠀⠀

$\begin{gathered}:\implies\sf 54 + 20 \\\\\\:\implies\sf 74 \end{gathered}$

Area of walls & ceiling of room is 74 m².

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$\begin{gathered}:\implies\sf Total \ cost \ of \ white \ washing = 74 \times 7.50 \\\\\\:\implies{\underline{\boxed{\frak{\pink{Rs. \ 555}}}}}\end{gathered}$

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$\therefore\;{\underline{\sf{Hence,Cost \ of \ white \ washing \ is \ {\textsf{\textbf{Rs. 555}}}.}}}$