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प्रश्न
Find the cost of sinking a tubewell 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.
उत्तर
Given data is as follows:
Height of the tube well = 280 m
Diameter = 3 m
Rate of sinking the tube well = Rs.3.60/m3
Rate of cementing = Rs.2.50/m2
Given is the diameter of the tube well which is 3 meters. Therefore,
`r = 3/2`m
Volume of the tube well = `pir^2h`
= `22/7 xx 3/2 xx3/2xx280`
= 1980 m2
Cost of sinking the tube well = Volume of the tube well × Rate for sinking the tube well
=1980 × 3.60
= Rs. 7128
Curved surface area = `2pirh`
= `2 xx 22/7 xx 3/2 xx 280 `
=2640 m2
Cost of cementing = `"Curved Surface Area " xx " Rate of cementing"`
= 2640 × 2.50
= Rs.6600
Therefore, the total cost of sinking the tube well is Rs.7128 and the total cost of cementing its inner surface is Rs.6600.
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