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29/07/2021 10:55 am
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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. (Assume π = 22/7)
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29/07/2021 10:56 am
Inner radius of hemispherical bowl, say r = diameter/2
= (10.5)/2 cm = 5.25 cm
Formula for Surface area of hemispherical bowl = 2πr2
= 2 × (22/7) × (5.25)2 = 173.25
Surface area of hemispherical bowl is 173.25 cm2
Cost of tin-plating 100 cm2 area = Rs 16
Cost of tin-plating 1 cm2 area = Rs 16 /100
Cost of tin-plating 173.25 cm2 area = Rs. (16 × 173.25)/100
= Rs 27.72
Therefore, the cost of tin-plating the inner side of the hemispherical bowl at the rate of Rs 16 per 100 cm2 is Rs 27.72.