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CBSE Class 9 Answered

A hemispherical bowl made of brass has inner radius 3.5 cm. Find the cost of tin-plating it on the inside at the rate of Rs 20 per 100 cm2.
Asked by Topperlearning User | 18 Oct, 2017, 03:17: PM
answered-by-expert Expert Answer

Inner radius of the hemispherical bowl (r) = 3.5 cm

begin mathsize 12px style Curved space surface space area space left parenthesis straight S right parenthesis space equals space 2 πr squared equals 2 cross times 22 over 7 cross times 3.5 squared space equals 77 space cm squared end style

Cost of tin plating 100 cm2 = Rs 20

begin mathsize 12px style Cost space of space tin space plating space 77 space cm squared space equals space Rs. space open parentheses 20 over 100 cross times 77 close parentheses equals space Rs. space 15.40 end style

Answered by | 18 Oct, 2017, 05:17: PM

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