Given,
Depth of tube well = 280 m
Diameter of tube well = 3 m
Radius of well = \(\frac{3}{2}\) = 1.5 m
so,
Volume = πr2h = \(\frac{22}{7}\) x 1.5 x 1.5 x 280 = 1980 m3
Cost of sinking tube well at rate Rs.3.60/m3 = 1980×3.60 = Rs.7128
Curved surface area = 2πrh = 2 x \(\frac{22}{7}\) x 1.5 x 280 = 2640 m2
Cost of cementing its inner curved surface at rate Rs.2.50/m2 = 2.50×2640 =Rs.6600