A well of diameter 3cm and 14cm deep is dug.The earth taken out of it has been evenly spread all around it in the shape of a circular ring of width 4cm to form an embankment.Find the height of the embankment?

Asked by satyendra | 20th Feb, 2014, 08:40: PM

Expert Answer:

As radius of well could not be in cm, let us solve the problem in meters.
Radius of the well = 3 over 2 space m
Depth of the well = 14 m
 
Volume of the well = pi cross times begin inline style open parentheses begin display style 3 over 2 end style close parentheses end style squared cross times 14 equals 99 space s q. m
Radius of the embankment = 3 over 2 plus 4 equals 11 over 2 space m
Volumne of the embankment is equal to 99 sq.m.
 
That is,
 
pi cross times begin inline style open parentheses begin display style 11 over 2 end style close parentheses end style squared cross times h equals 99 rightwards double arrow h equals fraction numerator 99 cross times 4 cross times 7 over denominator 121 cross times 22 end fraction almost equal to 1.04 space m
 
Thus, the height of the embankment is 1.04 m.

Answered by  | 21st Feb, 2014, 02:47: PM

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