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A led pencil consists of a cylindner of wood with a solid cylinder of graphite filled into it. the diameter of pencil is 7mm, the diameter of graphite is 1 mm and the length of the pencil is 10cm. Calculate the weight of the whole pencil, if the specific gravity of the wood is `0.7 (gm)/(cm)^3` and that of graphite is `2.1 (gm)/ (cm)^3`

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We have Diameter of the graphite cylinder =`1mm=1/10​cm `
Radius =`1/20​cm `
Length of the graphite cylinder =10cm
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