Question

find the number of coins 1.5 CM in diameter and 2 millimetre to be melted to form a right circular cylinder of height 10 cm and diameter 4.5 CM​

Answer 1

$\bold{\huge{\underline{\underline{\rm{Given:}}}}} \:$

$⟼\text{height = 10cm}$

$⟼ \text{diameter = 4cm}$

$\Huge{\underline{\underline{\mathfrak{ Solution \colon }}}}$

First we have to find the volume each coin.

$⟼\text{volume of each coin}$

$= \pi \times ( {0.75})^{2} \times 0.2$

$= 0.1125\pi \text{ {cm}}^{3}$

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Now,

$⟼ \text{volume of melted cylinder}$

$= \pi \times ( {2.25)}^{2} \times 10 = 50.625\pi \text{cm}$

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Number of coin required

$⟹ \frac{ \text{volume of each coin }}{ \text{volume of melted cylinder \: }}$

$⟹50.625π/0.1125π \:$

$⟹\text{no of coins = 450 coin}$

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