Question

16. A godown is 50 m long, 40 m broad and 10 m high. Find the cost of whitewashing its four wall and ceiling at rs 20 per squad metre

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Answer 1

Given:-

• Length = l = 50 m
• Breadth = b = 40
• Height = h = 10 m
• Rate of whitewashing = Rs. 20 per m²
• Walls to be whitewashed = 4 lateral walls + ceiling

To find:-

• Cost of whitewashing

Answer:-

❖ Area of 4 lateral walls:-

We know that

$\dag \underline{ \boxed{ \bf{ \blue{area \: of \: four \:lateral \: walls = 2(l + b)h \:\: sq. \:units}}}}$

❖ Calculating total area to be whitewashed:-

As the walls to be whitewashed are the four lateral walls and the ceiling,

Area to be whitewashed = Area of four walls + Area of ceiling

$\sf \longrightarrow Area\:to\:be\:whitewashed=2(l+b)h + lb\:sq.\:units$

Putting available values,

$\sf \longrightarrow Area\:to\:be\:whitewashed= 2(50 + 40)10 + (50\times 40)\:m^2$

$\sf{ \longrightarrow Area\:to\:be\:whitewashed= 1800 + 2000\: m^2}$

$\longrightarrow \sf Area\:to\:be\:whitewashed= 3800\:m^2$

❖ Calculating cost:-

Cost of whitewashing 1 m² = Rs. 20

So, cost of whitewashing 3800 m² = Rs. (20 * 3800) = Rs. 76,000

Hence, the answer is,

$\longrightarrow \underline{\underline{\sf{\green{ Rs. \: 76,000 }}}}$