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Question
A metal cuboid of measures 16 cm × 11 cm × 10 cm was melted to make coins. How many coins were made, if the thickness and diameter of each coin was 2 mm and 2 cm respectively? (π = 3.14)
Solution
Volume of cuboid = l × b × h
= 16 × 11 × 10
= 1760 cm3
Thickness of coin (H) = 2 mm
= 0.2 cm ...[∵ 1 cm = 10 mm]
Diameter of coin (D) = 2 cm
∴ Radius of coin (R) = `"D"/2 = 2/2` = 1 cm
∴ Volume of one coin = πR2H
= `3.14 xx 1^2 xx 0.2`
= 0.629 cm3
Number of coins that were made = `"Volume of cuboid"/"Volume of one coin"`
= `1760/0.629`
= 2800
∴ 2800 coins were made by melting the cuboid.
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