A well 20 m deep and 7 m ¡n diameter is dug. The earth taken out is s

1.	A well 20 m deep and 7 m ¡n diameter is dug. The earth taken out is spread to form a 22 m × 14 m embankment. Find the height of the embankment.
Answer» Given, Diameter of well = 7 m ∴ Radius of well (r) = \(\frac { 7 }{ 2 }\) m Depth of well (h) = 20m The volume of the soil taken out from well = πr²h = \(\frac { 22 }{ 7 }\) × \({ \left( \frac { 7 }{ 2 } \right) }^{ 2 }\) × 20 = 770 cm³. The length of plate form (L) = 22 m The breadth of plate form (B) = 14 m Let the height of plate form be H. Volume of plate form = L x B x H m³. = 22 × 14 × H m³ According to question Volume of plate form = volume of earth digut 22 × 14 × H = 770 H = \(\frac { 770 }{ 22\times 14 }\) = 2.5 m. Hence the height of plate form is 2.5 m.

A well 20 m deep and 7 m ¡n diameter is dug. The earth taken out is spread to form a 22 m × 14 m embankment. Find the height of the embankment.

Answer»

Given,

Diameter of well = 7 m

∴ Radius of well (r) = \(\frac { 7 }{ 2 }\) m

Depth of well (h) = 20m

The volume of the soil taken out from well = πr²h

= \(\frac { 22 }{ 7 }\) × \({ \left( \frac { 7 }{ 2 } \right) }^{ 2 }\) × 20

= 770 cm³.

The length of plate form (L) = 22 m

The breadth of plate form (B) = 14 m

Let the height of plate form be H.

Volume of plate form = L x B x H m³.

= 22 × 14 × H m³

According to question

Volume of plate form = volume of earth digut 22 × 14 × H = 770

H = \(\frac { 770 }{ 22\times 14 }\)

= 2.5 m.

Hence the height of plate form is 2.5 m.