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Question
A well is dug 20 m deep and it has a diameter of 7 m. The earth which is so dug out is spread out on a rectangular plot 22 m long and 14 m broad. What is the height of the platform so formed?
Solution
Height of the well = h m = 20 m
Diameter of the well = d m =7 m
Radius of the well = r m = 3.5 m
Volume of the well = πr2h = 22(3.5)2(20 ) m3= 770 m3
7
Volume of the well = Volume of the rectangular plot
Length of the rectangular plot = 22 m
Breadth of the rectangular plot =14 m
Volume of the rectangular plot = 770 m3 = (Length x Breadth x Height) of the rectangular plot \[\text{ Height }= \frac{770}{22 \times 14} = 2 . 5 m\]
Thus, the height of the platform is 2.5 m.
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