Height (h) cylindrical pillar = 3.5 m
Radius (r) of the circular end of pillar 50/2=25cm
CSA(curved surface area) of pillar =2πrh
=(2×22/7×0.25×3.5)m^2=(44×0.125)m^2=5.5m^2
Cost of painting 1m^2 area = Rs. 12.50
Cost of painting 5.5 m^2 area=Rs(5.5×12.50)
=Rs. 68.75
Therefore, the cost of painting the CSA of the pillar is Rs 68.75