Question

Estimate the cost of painting the inner wall of a well , if the depth of the well is 14ft and the diameter is 8ft . the cost of painting 2.5 sq. ft is 20 rupee? Explain​

Answer 1

Question:

Estimate the cost of painting the inner wall of a well , if the depth of the well is 14ft and the diameter is 8ft . the cost of painting 2.5 sq. ft is 20 rupee? Explain

Given:

Depth (height) of well (cylinder) = 14ft

Diameter of well (cylinder) = 8ft

Cost of painting 2.5 sq.ft = ₹20

Formula used:

$\bold{C.S.A\:of \: cylinder = 2\pi rh}$

Solution:

$\bold{C.S.A\:of \: cylinder = 2\pi rh}$

$\bold{ = \cancel{2}×\dfrac{22}{\cancel{7}}×\dfrac{8}{\cancel{2}}×\cancel{14}}$

$\bold{ = 22×8×2}$

$\bold{ = 352\:sq.ft}$

$\bold{Cost of painting 2.5 sq.ft = ₹20}$

$\bold{Cost of painting 1 sq.ft = \dfrac{₹20}{2.5}}$

$\bold{Cost of painting 352 sq.ft = \dfrac{₹20}{2.5}×352}$

$\bold{Cost of painting 352 sq.ft = \dfrac{₹7040}{2.5}}$

$\bold{Cost of painting 352 sq.ft = ₹2816}$

$\bold{∴\:The \:cost\:of\:painting\:the\:inner\:wall\:of\:the\:well=₹2816}$

Answer 2

Step-by-step explanation:

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