Question

A well of inner diameter 14 m is dug to a depth of 12 m. Earth taken out of it has been evenly spread all around it to a width of 7 m to form an embanknent. Find the height of the embankment so formed

Answer 1

hey

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•volume of well or earth dug out = πr^2h

diameter = 14m , radius =14/2=7m

depth / height = 15m

•now volume = 22/7×(7)^2×15

=105×22

•volume of embankment =π(R^2-r^2)×h

outer radius (R) = outer width + inner radius

= 7+7=14m

inner radius(r) = 7 m

height = ?

•volume = 22/7 ( 14^2-7^2)×h

=22/7×196-49×h

=22/7×147×h

=22×21×h

•earth taken out of well is spread over all around it forming a embankment

•volume of well = volume of embankment

105×22=21×22×h

105×22/21×22 = h

105×22/462=h

h=5m

hence height is 5 m

hope helped

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