Question

A well is dug 20 m deep and it has a diameter 7 m. The earth which is so dug out is
spread evenly on a rectangular plot 22 m long and 14 m broad. What is the height
of platform formed?
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Answer 1

5 m

Step-by-step explanation:

$volume \: of \: earth \: dug = volume \: of \: platform \\ \pi {r}^{2} h = lbh \\ \frac{22}{7} \times ( { \frac{7}{2} })^{2} \times 20 = 22 \times 14 \times h \\ h = \frac{22 \times 7 \times 7 \times 20}{7 \times 2 \times 22 \times 14} \\ h = 5$