A well with 14 m inside diameter is dug 10 m deep. Earth taken out of it has been evenly spread all round it to a width of 5 m form an embankment, then height if the embankment will be :

\(\frac{98}{15}\)  m

Radius = 14/2 = 7 m

Volume = πr²h

= \(\frac{22}{7}\) × 7 ×7 ×10

= 1540

It is taken out and spread width of 21m ,

R2 = (5 + 5 = 10 m )

V =  \(\frac{22}{7}\) × ( R² - r²)h

1540 =  \(\frac{22}{7}\) × ( 10² - 5²) h

1540 = \(\frac{22}{7}\) × ( ( 10² - 5²) h 

490 =   ( 75) h

h = \(\frac{98}{15}\) 

The correct answer is option (2) : \(\frac{98}{15}\) m