Correct Answer - Option 1 : Rs. 471
Given:
Diameter of each pillar = 0.4 m
∴ Radius of each pillar = r = 0.4/2 = 0.2 m
Height of the each pillar = 5 m
Formula used:
Area of cylinder = 2πrh
Calculation:
Curved surface area of each pillar = 2πrh
⇒ 2 × 3.14 × 0.2 × 5
⇒ 6.28 m2
Therefore, curved surface area of 25 pillar = 6.28 × 25 = 157 sq. m
Cost of cleaning = Rs. 3 per sq. m
∴ Cost of cleaning 25 pillars = Rs. 3 × 157
⇒ Rs. 471