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Probability

Question
CBSEENMA9003407
Wired Faculty App

10 cylindrical pillars of a building have to be painted. If the diameter of each pillar is 50 cm and the height 4 m, what will be the cost of painting at the rate of र 14 per square metre?

Solution
Diameter = 50 cm
therefore space space space Radius space left parenthesis straight r right parenthesis space equals space 50 over 2 space cm space equals space 25 space cm space space space space space space space space space space space space space space space space space space space space space equals space 25 over 100 space straight m space equals space 1 fourth space straight m

Height (h) = 4 m
∴ Curved surface area of 1 pillar = 2straight pirh

equals 2 cross times 22 over 7 cross times 1 fourth cross times 4 equals 44 over 7 space straight m squared
Curved surface area of 10 pillars
equals 44 over 7 cross times 10 space straight m squared equals 440 over 7 space straight m squared
∴ Cost of painting at the rate of र 14 per square metre = 440 over 7 cross times 14 = र 880.

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