Question

The length, breadth and height of a room are 5 cm, 6 cm and 10 cm respectively. Find
the cost of white washing the four walls at the rate of Rs. 8 per square metre.​

Answer 1

Answer:

The cost of white washing the four walls will be ₹1,760

Step-by-step explanation:

Given dimensions of the room :

➪ l (length) = 5cm.

➪ b (width) = 6cm.

➪ h (height) = 10cm.

Step 1 : Find the surface area of the room :

The room is cuboidal shaped.

Lateral surface area of a cuboid is given by :

→ 2h (l + b)

→ 2*10(5 + 6)

→ 20(11)

→ 220m²

Step 2 : Find the cost of white washing :

Unitary method :

∵ One m² of white washing costs ₹8

∴ Total cost of white washing the four walls :

→ ₹8 × 220

→ ₹1,760

Answer 2

Given :-

→ Length of a room = 5 cm

→ Breadth of a room = 6 cm

→ Height of a room = 10 cm

To Find :-

→ Cost of whitewashing that room at the rate of Rs. 8 per m²

Solution :-

→ We need to find the lateral surface area

→ As we know that

$\underline{\bf{\dag} \:\mathfrak{Lateral\;surface\;area\;=2h(l+b)}}$

Where ,

h = height

l = length

b = breadth

→ Let's find out by putting the values in the formula !

$\sf \implies 2\times10(5+6)$

$\sf \implies 20 \times 11 = 220 \; cm^{2}$

∴ Lateral surface area is 220 cm²

→ Now let's find the cost of whitewashing

Cost per m² = Rs. 8

Cost of 220 m² = 220 × 8

$\sf \implies Rs.\;1760$

∴ Cost of whitewashing is Rs. 1760

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