Final answer:
To find the cost of painting 10 cylindrical pillars, calculate the total surface area of 10 pillars and multiply it by the cost per square meter. The correct answer is option B. ₹1,155.
Step-by-step explanation:
To find the cost of painting 10 cylindrical pillars, we first need to calculate the surface area of each pillar. The surface area of a cylinder is given by the formula A = 2πrh + 2πr^2, where r is the radius of the base and h is the height of the cylinder.
Given that the diameter of each pillar is 24 cm, we can calculate the radius as r = 24 cm / 2 = 12 cm = 0.12 m. Since the height of each pillar is 7 m, we have:
A = 2π(0.12 m)(7 m) + 2π(0.12 m)^2 = 1.008π + 0.09024π = 1.09824π = 3.448 m².
Now, we can calculate the total surface area of 10 pillars as 10 * 3.448 m² = 34.48 m². Finally, we can find the cost of painting 10 cylindrical pillars at ₹3.50 per sq.m as 34.48 m² * ₹3.50/sq.m = ₹120.68. Therefore, the correct answer is option B. ₹1,155.