Q5 of 75 Page 225

A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of Rs 16 per 100 cm2

Inner radius (r) = = 5.25 cm

Surface area of hemispherical bowl = 2πr2


= 2 * * 5.25 * 5.25


= 173.25 cm2


Cost of tin-plating 100 cm2 area = Rs 16


Cost of tin-plating 173.25 cm2 area = ()


= Rs 27.72


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