there are 20 cylindrical pillars in a building each having a diameter of 50 and height 4 CM find the cost of cleaning them at 14 per m2
Answers
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Answer:
The cost of cleaning 20 pillars is Rs 17.60 approximately.
Step-by-step-explanation:
We have given that,
For cylindrical pillars,
Diameter ( d ) = 50 cm
∴ Radius ( r ) = d / 2 = ( 50 / 2 ) cm
Height ( h ) = 4 cm
Rate of cleaning = Rs 14 per m²
As the cylinderical pillars are to be cleaned, only curved surface area needs to be calculated.
We know that,
Curved surface area of cylinder = 2 π r h
⇒ CSA of cylinder = 2 * ( 22 / 7 ) * ( 50 / 2 ) * 4
⇒ CSA of cylinder = 2 ÷ 2 * ( 22 * 50 * 4 ) / 7
⇒ CSA of cylinder = ( 22 * 200 ) / 7
⇒ CSA of cylinder = 4400 ÷ 7
⇒ CSA of cylinder = 628.571
∴ Curved surface area of 1 cylinderical pillar = 628.571 cm²
Now,
Curved surface area of 20 cylindrical pillars = 20 * 628.57 cm²
⇒ Curved surface area of 20 cylindrical pillars = ( 20 * 628.571 / 10000 ) m²
⇒ Curved surface area of 20 cylindrical pillars = 628.571 ÷ 500
⇒ Curved surface area of 20 cylindrical pillars = 1.257 m²
Now,
Cost of cleaning 20 pillars = Curved surface area of 20 pillars * Rate of cleaning per m²
⇒ Cost of cleaning 20 pillars = 1.257 * 14
⇒ Cost of cleaning 20 pillars = Rs 17.598
∴ The cost of cleaning 20 pillars is Rs 17.60 approximately.