The internal and external diameters of a hollow hemispherical vessel are 24 cm and 25 cm respecttively. If the cost of painting 1 sq.cm of the surface area is Rs. 0.05, find the total cost of painting the vessel all over.

Here is the solution to your question-

external diameter of hollow hemispherical vessel = 25 cm

the external radius R = 25/2 = 12.5 cm

internal diameter of hollow hemispherical vessel = 24 cm

the internal radius r = 24/2 = 12 cm

the surface area of the hollow hemispherical vessel

= curved surface area of the external hemisphere + curved surface area of internal hemisphere+ area of the top

since the cost of the paint 1 sq cm is Rs.0.05/-

therefore the total cost

thus total cost to the nearest rupee to paint the vessel all over is Rs. 96.

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