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Question
Metallic discs of radius 0.75 cm and thickness 0.2 cm are melted to obtain 508.68 cm3 of metal. Find the number of discs melted (use π = 3.14).
Solution
Radius of metallic disc = 0.75 cm
Thickness of disc = 0.2 cm
Total volume of material which will be used in forming/melting of disc = 508.68 cm3
∴ Material required for one disc = Volume of cylinder
= πr2h
= `22/7 xx 0.75 xx 0.75 xx 0.2` ...[∵ Shape of a disc is a cylinder]
= 3.14 × 0.75 × 0.75 × 0.2
= 0.35325 cm3
Number of disc can be melted
= `"Total volume of metal obtained after melting"/"Volume of one disc"`
= `508.68/0.35325`
= 1440 discs
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