Find the cost of sinking a tube-well 280 m deep, having a diameter 3m at the rate of Rs 15 per cubic metre. Find also the cost of cementing its inner curved surface at Rs 10 per square metre.

Answer

Rs 29700, Rs 26400

Explanation

Here, r = 1.5 m and h = 280 m
Cost of sinking the tube-well `= Rs {(22)/(7) xx (15)/(10) xx (15)/(10) xx 280 xx 15} = Rs 29700`
Cost of cementing its inner curved surface
`= Rs (2 xx (22)/(7) xx (15)/(10) xx 280 xx 10) = Rs 26400`