Question

A 16 m deep well with diameter 3.5 m is dug up and the earth from it is spread evenly to platform 27.5 m by 7 m . find the height of the platform

Answer 1

Volume of well = volume of platform
πr×rh = lbh
22/7×35/20×35/20×16 = 275/10×7×x
x = 8/10

Answer 2

Answer:

The height of the platform is 80 cm.

Step-by-step explanation:

Given :  

Height of deep well which is in the form of cylinder, H = 16 m

Diameter of the deep well = 3.5 m

Radius (r) of the deep well = 3.5/2 m = 1.75 m

Length of the platform (l) = 27.5 m

Breadth of the platform (b) = 7 m

Let the height of the platform be ‘h’ m.

Here, the earth obtained from digging the well of cylindrical shape is used to make a platform of cuboidal shaped. So the volume of Earth will be equal to the volume of cylindrical well and it will be equal to volume of cuboidal platform.

Volume of the deep well (cylinder)  = Volume of cuboidal platform.

πr²H = lbh

π × (1.75)²  ×16 = 27.5  × 7 × h  

22/7 × 1.75 × 1.75 × 16 = 27.5 × 7 × h

h = (22× 1.75 × 1.75 × 16) / (27.5 × 7 × 7)

h = (22 × 0.25 × 0.25 × 16) / 27.5

h  = 22  / 27.5  

h = 0.8 m = 0.8 × 100 = 80 cm  

[1 m = 100 cm ]

height of the platform = 80 cm

Hence, the height of the platform is 80 cm.

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