Question

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

Answer 1

Given⤵️

•Depth of the well =14 ft

• Diameter = 8 ft

•The cost of painting 2.5 sq. ft is 20.

To Find⤵️

the cost of painting the innerwall of a well

Solution ⤵️

Diameter =8 ft

So, radius = 4 ft

CSA of cylindrical well = 2πrh

= 2 * 22/7 * 4 * 14

= 352 ft^2

So,

Cost = rate per unit area * area

= (20 / 2.5) * 352

= 8 * 352

= 2816

Therefore the cost of painting the inner well = Rs 2816