Question

The length, breadth and height of a room are 5 m, 4 m and 3 m
respectively. Find the cost of whitewashing the walls and the ceiling
of the room @ Rs.7.50 per m2

Answer 1

Answer:

rs. 555

Step-by-step explanation:

l = 5m, b = 4m, h = 3m

It is given that whitewashing is to bo done only on walls and ceiling.

Therefore, the area of whitewashing = area of walls + area of ceiling

=2lh+2bh+lb

=(2×5×3×2×4×3×5×4) m²

=74m²

Cost of whitewashing per m² = Rs. 7.50

Therefore, the cost of whitewashing 74m² = Rs.(74 × 7.50)

=Rs. 555

Answer 2

$\bf \huge {\underline {\underline \red{AnSwEr}}}$

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Given

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• Length = 5m

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• Breadth = 4cm

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• Height = 3m

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To Calculate

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• Cost of white washing the walls and ceiling

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Concept used

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• $\bf L.S.A \: of \: cuboid = 2(l + b) \times h$

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• Area of rectangle

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Solution

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Area of room used in white washing = L.S.A of room + area of ceiling

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$\bf \implies [2(l + b) \times h] +[ l \times b]$

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$\bf \implies 2(5 + 4) \times 3 + 5 \times 4$

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$\bf \implies 6 \times 9 + 20$

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$\bf \implies 54 + 20$

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$\bf \implies {74m}^{2}$

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Cost of white washing = Rs. 7.50 per metre square

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$\bf = 74 \times 7.50$

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$\bf =Rs .555$

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Hence, Cost of white washing is Rs. 555.