Curved surface area of cylindrical pillar is given as A =2πrh, where 'r' is base radius and 'h' is height of the cylinder. So curved surface area of each pillar A =2×π×0.35×5=11m2 Given there are 30 cylindrical pillars. The curved surface area of half the number of pillars = 15 × A = 165 . Given rate of painting is Rs. 10 per m2 The cost of painting curved surface of half the number of pillars = Curved surface area × rate of painting =165×10=Rs.1650