Question

A open box is made of wood 3 cm thick. Its external length, breadth and height are 1.48
1.16 m and 8.3 m. Find the cost of painting the inner surface at 50 per square metre.
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Answer 1

Answer:

23.2667$

Step-by-step explanation:

length: 148-3=145

breadth: 116-3=113

height: 830-3=827

2(145x113) + 2(113x827) + 2(145x827)= 465334cm3=0.465334m3

0.465334x50=23.2667$

Answer 2

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$\huge{\underline{\underline{\sf{\green{SOLUTION:-}}}}}$

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$\sf{\underline{\red{Answer-}}}$

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• The cost of painting the inner surface at 50 per square metre is Rs. 279.70

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$\sf{\underline{\red{Given-}}}$

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• A open box is made of wood 3 cm thick. Its external length, breadth and height are 1.48, 1.16 m and 8.3 m.

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$\sf{\underline{\red{Find-}}}$

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• We have to find the cost of painting the inner surface at 50 per square metre.

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$\sf{\underline{\red{Explanation-}}}$

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$\sf\longrightarrow Length = 1.48m = 148 cm.$

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$\sf\longrightarrow \: Breadth = 1.16m = 116 cm.$

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$\sf\longrightarrow \: Height = 8.3m = 83cm.$

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$\sf\longrightarrow \: Thickness = 3cm.$

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$\sf{\underline{\red{Inner\: Dimensions-}}}$

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$\sf \longrightarrow\: Length \: (148 - 2 \times 3)cm=142cm$

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$\sf \longrightarrow\: Breadth \: (116 - 2 \times 3)cm=110cm$

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$\sf\longrightarrow \: Height \: (83-3)cm=80cm$

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$\sf{\underline\blue{Formula\:Used\:Here-}}$

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⠀$\bigstar\:\:\:\boxed{\sf{\red{Inner \: Surface \: Area=2(l+b)+lb}}}$

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$\sf{\underline{\pink{Putting\:the\:values:-}}}$

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$\sf\longrightarrow2(142 \: + \: 100) \: 80+142 \times 110 \: {cm}^{2}$

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$\sf\longrightarrow2(252) \: 80+142 \times 110 \: {cm}^{2}$

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$\sf\longrightarrow2 \times 252 \times \: 80+15,620 \: {cm}^{2}$

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$\sf\longrightarrow2 \times 20,160+15,620 \: {cm}^{2}$

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$\sf\longrightarrow40,320+15,620 \: {cm}^{2}$

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$\sf\longrightarrow55,940\: {cm}^{2}$

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$\sf\longrightarrow559.40\: {m}^{2}$

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$\sf{\underline{\pink{Now\: Calculate\:Cost\:Of\: Painting-}}}$

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$\sf\longrightarrow55.940 \times Rs. 50$

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$\sf\longrightarrow \: Rs279.70$

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• Hence, the cost of painting the inner surface at 50 per square metre is Rs. 279.70.

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