Question

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

2816 rupees

Explanation:

here , depth = 14 ft

diameter = 8 feet

so , radius = 4 ft

We will paint it in its C.S.A.

C.S.A. of a cylindrical well

= 2πrh

= 2×(22/7)× 4 × 14

= 352 ft²

so,

cost = rate per unit area × area

= (20/2.5)×352

= 8×352

= 2816

so,the cost of the painting will be 2816 rupees