Question

a 20m deep pit with diameter 7 m is dug up and the earth from digging is spread evenly to form a platform 22m*14m .the height of the platform is

Answer 1

Diameter = 7 m

Radius = 7/2 m

Depth = 20 m

Volume of earth dug out= πr²h

= 22/7 × 7/2 × 7/2 × 20

= 770 m³

Area of the rectangular plot where the mud is spread = 22 x 14

Let the height of the plotfarm be h metres.

Volume of the plot form = Volume of the mud taken from the well

22 x 14 x h = 770

h = 770 / 22x14

h = 2.5 m

Hope it helps u

Answer 2

⇒ Given:- Height (h) of well :- 20m

Diameter (d) :- 7 m

Radius (r) :- 7/2 m

Volume of earth platform :- 22 m by 14m

⇒ To find :- Height of the platform:- ?

⇒ Solution:-

Volume of cylinder of radius 7/2 m and height 20 m

Volume of cylinder :- π(r^2)(h)

= 22/7×(7/2^2)×20 m^3

= 770 m^3

Let the height raised by 22 m × 14 m platform be equal to h metres

Therefore,

Volume of the earth in platform = Volume of the earth taken out of the well

22 × 14 × h = 770

h = 770/22 × 14 m

h = 5/2 m

h = 2.5 m

Hence , the height of the platform is 2.5 m.