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प्रश्न
In the middle of a rectangular field measuring 30 m × 20 m, a well of 7 m diameter and 10 m depth is dug. The earth so removed is evenly spread over the remaining part of the field. Find the height through which the level of the field is raised.
उत्तर
Radius of dug `= 7/2 m`
Depth of dug = 10 m
The volume of dug
`= pi(7/2)^2 xx 10`
`= 22/7 xx 49/4 xx 10`
The volume of dug = 385 m3
Let the height through which the level of the field is raised will be x.
But, volume of dug = volume of earth spread over field.
`385 = 30 xx 20 xx x `
`x = (385) / (30 xx 20)`
`x = 68.6cm`
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