Options:
A) 10 m
B) 11 m
C) 11.2 m
D) 11.5 m
Show Answer
Answer:
Correct Answer: C
Solution:
- [c] Radius of the base of well $ =\frac{20}{2}=10,m $
Volume of the earth taken out
$ =\pi r^{2}h=\frac{22}{7}\times 10^{2}\times 14 $
Let the height of embankment be x m.
Here, $ R=15m, $ $ r=10m $
Then, volume
$ =\pi (R^{2}-r^{2})\times x=\frac{22}{7}\times (15^{2}-10^{2})\times x $
$ =\frac{22}{7}\times 25\times 5\times x $
Clearly, $ \frac{22}{7}\times 25\times 5\times x=\frac{22}{7}\times 10^{2}\times 14 $
$ \Rightarrow $ $ x=\frac{100\times 14}{25\times 5}=11.2m $