Find the cost of sinking a tube well 280 m deep, having diameter 3 m a

1.	Find the cost of sinking a tube well 280 m deep, having diameter 3 m at the rate of Rs. 3.60 per cubic metre. Find also the cost of cementing its inner curved surface at Rs. 2.50 per square metre.
Answer» 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

Find the cost of sinking a tube well 280 m deep, having diameter 3 m at the rate of Rs. 3.60 per cubic metre. Find also the cost of cementing its inner curved surface at Rs. 2.50 per square metre.

Answer»

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