Question

Earth taken out on digging a circular tank of diameter 17.5m is spread all around the tank uniformly to a width of 4m to form an embankment of height 2m .calculate the depth of the circular tank correct to 2 decimal place

Answer 1

diameter of circular tank is equal to 17.5 M

therefore, radius is equal to 17.5/2 m = 8.75 M

width of earth embankment = 4 m

height =2 m

let it be the depth of well then volume of earth taken out of πr^2h

22 875 875
---- ×----- × ----- × h
7 100 100

22/7 × 35/4 × 35/4 ×h ...........(1)

volume of platform formed by Earth taken out

π {(51/4)^2 - (35/4^2)} × 2

2 × 22/7 {51/4 + 35/4} {51/4 - 35/4}

44/7 × 86/4 × 16/4

3784/7 m^2........(2)

from (1) and (2)

h=2.246 = 2.25 m

depth of tank = 2.25

Answer 2

Answer:

2.25 m

Step-by-step explanation:

Let the depth of the circular tank = h metres.

The embankment is a circular path, 4 m wide, round the tank and the radius of the tank is 17.5/2 metres.

Volume of the earth dug out = volume of the tank = 22/7 × ( 17.5/2)² × h cu m.

Outer radius of the embankment = (17.5/2+4) m = 25.5/2 m

Volume of the embankment = 22/7 {(25.5/2)² - (17.5/2)²} × 2 cu m

But, volume of the embankment = volume of the earth dug out.

Therefore, 22/7 {(25.5/2)² - (17.5/2)²} × 2 = 22/7 ×(17.5/2)²×h

h = 2.25 m ( Ans.)